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Showing papers in "Breast Cancer Research and Treatment in 2018"


Journal ArticleDOI
TL;DR: PD-L1 expression in tumor-associated immune cells may be associated with a higher probability of clinical response to avelumab in MBC, and showed an acceptable safety profile and clinical activity in a subset of patients with MBC.
Abstract: Agents targeting programmed death receptor 1 (PD-1) or its ligand (PD-L1) have shown antitumor activity in the treatment of metastatic breast cancer (MBC). The aim of this study was to assess the activity of avelumab, a PD-L1 inhibitor, in patients with MBC. In a phase 1 trial (JAVELIN Solid Tumor; NCT01772004), patients with MBC refractory to or progressing after standard-of-care therapy received avelumab intravenously 10 mg/kg every 2 weeks. Tumors were assessed every 6 weeks by RECIST v1.1. Adverse events (AEs) were graded by NCI-CTCAE v4.0. Membrane PD-L1 expression was assessed by immunohistochemistry (Dako PD-L1 IHC 73-10 pharmDx). A total of 168 patients with MBC, including 58 patients with triple-negative breast cancer (TNBC), were treated with avelumab for 2–50 weeks and followed for 6–15 months. Patients were heavily pretreated with a median of three prior therapies for metastatic or locally advanced disease. Grade ≥ 3 treatment-related AEs occurred in 13.7% of patients, including two treatment-related deaths. The confirmed objective response rate (ORR) was 3.0% overall (one complete response and four partial responses) and 5.2% in patients with TNBC. A trend toward a higher ORR was seen in patients with PD-L1+ versus PD-L1− tumor-associated immune cells in the overall population (16.7% vs. 1.6%) and in the TNBC subgroup (22.2% vs. 2.6%). Avelumab showed an acceptable safety profile and clinical activity in a subset of patients with MBC. PD-L1 expression in tumor-associated immune cells may be associated with a higher probability of clinical response to avelumab in MBC.

509 citations


Journal ArticleDOI
TL;DR: The development of drugs targeting the PI3K/AKT/mTOR pathway for the treatment of TNBC is an evolving field that should take into account the efficacies and toxicities of new agents in addition to their interactions with different cancer pathways.
Abstract: Triple-negative breast cancer (TNBC) accounts for approximately 20% of breast cancer cases Although there have been advances in the treatment of hormone receptor-positive and human epidermal growth factor receptor 2-positive breast cancers, targeted therapies for TNBC remain unavailable In this narrative review, we summarize recent discoveries related to the underlying biology of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) pathway in TNBC, examine clinical progress to date, and suggest rational future approaches for investigational therapies in TNBC As with other subtypes of breast cancer, aberrations in the PI3K/AKT/mTOR pathway are common in TNBC Preclinical data support the notion that these aberrations predict TNBC inhibition by targeted agents In a recently published phase 2 clinical trial, an AKT inhibitor (ipatasertib) improved outcomes in a subset of patients with metastatic TNBC when combined with paclitaxel in the first-line setting In addition, new compounds with distinct specificity and potency targeting different PI3K/AKT/mTOR components and cognate molecules (eg, mitogen-activated protein kinase) are being developed These agents present a wide range of toxicity profiles and early efficacy signals, which must be considered prior to the advancement of new agents in later-phase clinical trials The development of drugs targeting the PI3K/AKT/mTOR pathway for the treatment of TNBC is an evolving field that should take into account the efficacies and toxicities of new agents in addition to their interactions with different cancer pathways

286 citations


Journal ArticleDOI
TL;DR: Assessing nearly 14,000 women from a contemporary United States database, this is the largest known study examining the relationship between response to NC and molecular subtype and predictors thereof and degree of response is associated with OS.
Abstract: This is the largest study to date evaluating response rates and pathologic complete response (pCR) and predictors thereof, based on molecular subtype, in women with breast cancer having undergone neoadjuvant chemotherapy (NC). The National Cancer Database was queried for women with cT1-4N1-3M0 breast cancer having received NC. Patients were divided into four subtypes: luminal A, luminal B, Her2, or triple negative (TN). Multivariable logistic regression ascertained factors associated with developing pCR. Kaplan–Meier analysis evaluated overall survival (OS) between patients by degree of response to NC when stratifying patients by subtype. Of a total of 13,939 women, 322 (2%) were luminal A, 5941 (43%) luminal B, 2274 (16%) Her2, and 5402 (39%) TN. Overall, 19% of all patients achieved pCR, the lowest in luminal A (0.3%) and the highest in Her2 (38.7%). Molecular subtype was an independent predictor of both pCR and OS in this population. Clinical downstaging was associated with improved survival, mostly in women with luminal B, Her2, and TN subtypes. Subgroup analysis of the pCR population demonstrated 5-year OS in the luminal B, Her2, and TN cohorts of 93.0, 94.2, and 90.6%, respectively (Her2 vs. TN, p = 0.016). Assessing nearly 14,000 women from a contemporary United States database, this is the largest known study examining the relationship between response to NC and molecular subtype. Women with luminal A disease are the least likely to undergo pCR, with the highest rates in Her2 disease. Degree of response is associated with OS, especially in luminal B, Her2, and TN patients. Despite the comparatively higher likelihood of achieving pCR in TN cases, this subgroup may still experience a survival detriment, which has implications for an ongoing national randomized trial.

180 citations


Journal ArticleDOI
TL;DR: The study of radiomics in BC patients is a new and emerging translational research topic and high-quality prospective and reproducible studies are needed to further potential application.
Abstract: To perform a rapid review of the recent literature on radiomics and breast cancer (BC). A rapid review, a streamlined approach to systematically identify and summarize emerging studies was done (updated 27 September 2017). Clinical studies eligible for inclusion were those that evaluated BC using a radiomics approach and provided data on BC diagnosis (detection or characterization) or BC prognosis (response to therapy, morbidity, mortality), or provided data on technical challenges (software application: open source, repeatability of results). Descriptive statistics, results, and radiomics quality score (RQS) are presented. N = 17 retrospective studies, all published after 2015, provided BC-related radiomics data on 3928 patients evaluated with a radiomics approach. Most studies were done for diagnosis and/or characterization (65%, 11/17) or to aid in prognosis (41%, 7/17). The mean number of radiomics features considered was 100. Mean RQS score was 11.88 ± 5.8 (maximum value 36). The RQS criteria related to validation, gold standard, potential clinical utility, cost analysis, and open science data had the lowest scores. The majority of studies n = 16/17 (94%) provided correlation with histological outcomes and staging variables or biomarkers. Only 4/17 (23%) studies provided evidence of correlation with genomic data. Magnetic resonance imaging (MRI) was used in most studies n = 14/17 (82%); however, ultrasound (US), mammography, or positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-d-glucose integrated with computed tomography (18F FDG PET/CT) was also used. Much heterogeneity was found for software usage. The study of radiomics in BC patients is a new and emerging translational research topic. Radiomics in BC is frequently done to potentially improve diagnosis and characterization, mostly using MRI. Substantial quality limitations were found; high-quality prospective and reproducible studies are needed to further potential application.

178 citations


Journal ArticleDOI
TL;DR: With the increasing incidence of detected breast cancer and the improvements in treatment and consequently survival, knowledge about prevalence, and factors related to treatment late effects of chronic pain is highly relevant for potential prevention or management without negatively impacting quality of life.
Abstract: To investigate prevalence and risk factors associated with self-reported chronic pain, and other symptoms related to breast cancer or its treatment among breast cancer survivors (BCS). A cross-sectional study of a random sample of 410 female BCS, members of “Leumit” healthcare fund, diagnosed with primary nonmetastatic invasive breast cancer in the years 2002–2012. The study questionnaire included questions on health-related quality of life, pain symptoms, and was completed by all women contacted. A total of 305 BCS (74%), with a median of 7.4 years since diagnosis reported chronic pain, of whom 84% had moderate pain, and 97% experienced pain at least 1–3 days/week. Other symptoms were paresthesia (63%), allodynia (48%), and phantom sensations (15%). Report of pain symptoms, alone or combined, was significantly associated with poorer quality of life. In multivariable analyses, chronic pain was positively associated with mastectomy compared to breast-conserving surgery [Odds ratio (OR), 3.54; 95% confidence interval (CI) 1.46–8.59; P = 0.005], radiotherapy compared to non-radiotherapy (OR 2.96; 95% CI 1.43–6.12; P = 0.003), breast cancer stage at diagnosis—regional versus localized (OR 3.63; 95% CI 2.00–6.57; P < 0.001), and inversely with age (OR per one-year increment, 0.96; 95% CI 0.94–0.99; P = 0.002), and with time since diagnosis (OR per one-year increment, 0.82; 95% CI 0.75–0.90; P < 0.001). With the increasing incidence of detected breast cancer and the improvements in treatment and consequently survival, knowledge about prevalence, and factors related to treatment late effects of chronic pain is highly relevant for potential prevention or management without negatively impacting quality of life.

127 citations


Journal ArticleDOI
TL;DR: Since p53 is mutated in the vast majority of TN breast cancers, compounds such as APR-246, PK11007, and COTI-2 are potential treatments for patients with this subform of the disease.
Abstract: The aim of this article is to discuss mutant p53 as a possible therapeutic target and biomarker for breast cancer. TP53 (p53) is the most frequently mutated gene in invasive breast cancer. Although mutated in 30–35% of all cases, p53 is mutated in approximately 80% of triple-negative (TN) tumors (i.e., tumors negative for ER, PR, and HER2). Because of this high prevalence, mutated p53 is both a potential biomarker and therapeutic target for patients with breast cancer, especially for those with the TN subtype. Although several retrospective studies have investigated a potential prognostic and therapy predictive role for mutant p53 in breast cancer, the results to date are mixed. Thus, at present, mutant p53 cannot be recommended as a prognostic or therapy predictive biomarker in breast cancer. In contrast to the multiple reports on a potential biomarker role, few studies had until recently, investigated mutant p53 as a potential target for breast cancer treatment. In the last decade, however, several compounds have become available which can reactivate mutant p53 protein and convert it to a conformation with wild-type properties. Some of these compounds, especially PRIMA-1, APR-246 PK11007, and COTI-2, have been found to exhibit anticancer activity in preclinical models of breast cancer. Since p53 is mutated in the vast majority of TN breast cancers, compounds such as APR-246, PK11007, and COTI-2 are potential treatments for patients with this subform of the disease. Further research is necessary to identify a potential biomarker role for mutant p53 in breast cancer.

123 citations


Journal ArticleDOI
TL;DR: Differences in tumor characteristics by age and race/ethnicity suggest opportunities for further research into personal and cultural factors that may influence breast cancer risk among younger women.
Abstract: Younger women diagnosed with breast cancer have poorer prognoses and higher mortality compared to older women. Young black women have higher incidence rates of breast cancer and more aggressive subtypes than women of other races/ethnicities. In this study, we examined recent trends and variations in breast cancer incidence among young women in the United States. Using 2004–2013 National Program of Cancer Registries and Surveillance, Epidemiology, and End Results Program data, we calculated breast cancer incidence rates and trends and examined variations in stage, grade, and tumor subtype by age and race/ethnicity among young women aged 20–49 years. The majority of breast cancer cases occurred in women aged 40–44 and 45–49 years (77.3%). Among women aged < 45 years, breast cancer incidence was highest among black women. Incidence trends increased from 2004 to 2013 for Asian or Pacific Islander (API) women and white women aged 20–34 years. Black, American Indian or Alaska Native, and Hispanic women had higher proportions of cases diagnosed at later stages than white and API women. Black women had a higher proportion of grade III–IV tumors than other racial/ethnic groups. Across all age groups, incidence rates for triple-negative breast cancer were significantly higher in black women than women of other races/ethnicities, and this disparity increased with age. Breast cancer among young women is a highly heterogeneous disease. Differences in tumor characteristics by age and race/ethnicity suggest opportunities for further research into personal and cultural factors that may influence breast cancer risk among younger women.

106 citations


Journal ArticleDOI
TL;DR: The prevalence of germline TP53 mutations, the risk of breast cancers and other cancers in mutation carriers and management implications for women with breast cancer and unaffected women are described.
Abstract: This review describes the prevalence of germline TP53 mutations, the risk of breast cancer and other cancers in mutation carriers and management implications for women with breast cancer and unaffected women. Literature review of English language papers available through PubMed. Women who carry germline mutations in the TP53 gene have a very high risk of breast cancer of up to 85% by age 60 years. Most of these breast cancers are early onset with a median age at diagnosis of 34 years. Approximately 5–8% of women presenting with breast cancer under 30 years old have a germline TP53 gene mutation. Breast cancers in women with TP53 mutations are more likely to be hormone receptor positive and/or Her2 positive. Mastectomy is recommended over lumpectomy in TP53 mutation carriers who have breast cancer so that adjuvant breast radiotherapy can be avoided. Risk-reducing surgery should be considered due to the high contralateral breast cancer risk. Mutation carriers are at high risk of various childhood and adult-onset cancers with a very lifetime risk of malignancy, the commonest malignancies being breast cancer and soft tissue sarcoma. In unaffected female mutation carriers, MRI breast screening or risk-reducing surgery is recommended. The optimal surveillance for other cancers is currently unclear and should ideally be performed as part of a clinical trial. Identifying a TP53 mutation in a gene panel test is a challenging result for the patient and clinician due to the high risk of second primaries and the lack of consensus about surveillance.

105 citations


Journal ArticleDOI
TL;DR: The relationship between tumour size, lymph node status and distant metastases in patients with invasive breast cancer is not linear, calling into question the conventional model that the capacity for a primary breast tumour to metastasize increases as the tumour enlarges.
Abstract: In patients with breast cancer, increasing tumour size at diagnosis is associated with an increased likelihood of axillary lymph node involvement and increased breast cancer-specific mortality. However, this relation is based on studies which combine all tumours smaller than 1.0 cm in a single category and all tumours larger than 5.0 cm in another category. This coarse classification may obscure a nuanced description of the effects of tumour size across the full range of possible sizes. We examined the relationship between primary tumour size, lymph node status and distant metastases in a cohort of 819,647 women diagnosed with first primary invasive breast cancer from 1990 to 2014 in the Surveillance, Epidemiology and End Results (SEER) registries database. All patients in the cohort had a known primary tumour size between 1 and 150 mm in greatest dimension. Primary tumour size was examined as a continuous (1–150 mm) and categorical variable (15 size groups; 10-mm intervals). For each 1- or 10-mm size group, we determined the proportion of patients with positive lymph nodes at diagnosis, the proportion of patients with distant metastases at diagnosis and the actuarial cumulative risk of breast cancer-specific mortality at 15 years from diagnosis. Among 819,647 patients with invasive breast tumours between 1 and 150 mm in size, there was a non-linear correlation between increasing tumour size and the prevalence of lymph node metastases at diagnosis (% node-positive), the prevalence of distant metastases at diagnosis (% stage IV) and the 15-year rate of breast cancer-specific mortality across the entire size spectrum. For very small tumours (under 10 mm) and for very large tumours (larger than 60–90 mm) there was little correlation between tumour size and metastasis risk. The relationship between tumour size, lymph node status and distant metastases in patients with invasive breast cancer is not linear. This calls into question the conventional model that the capacity for a primary breast tumour to metastasize increases as the tumour enlarges.

100 citations


Journal ArticleDOI
TL;DR: 16 weeks of resistance and HIIT was effective in preventing increases in CRF and in reducing symptom burden for patients during chemotherapy for breast cancer, adding to a growing body of evidence supporting the inclusion of structured exercise prescriptions, including HIIT, as a vital component of cancer rehabilitation.
Abstract: PURPOSE: Exercise training is an effective and safe way to counteract cancer-related fatigue (CRF) and to improve health-related quality of life (HRQoL). High-intensity interval training has proven ...

97 citations


Journal ArticleDOI
TL;DR: DBT-supplemented screening resulted in significant increases in screen-detected cancers and specificity, however, no significant change was observed in the rate, size, node status, or grade of interval cancers.
Abstract: Digital breast tomosynthesis (DBT) has the potential to overcome limitations of conventional mammography This study investigated the effects of addition of DBT on interval and detected cancers in population-based screening Oslo Tomosynthesis Screening Trial (OTST) was a prospective, independent double-reading trial inviting women 50–69 years biennially, comparing full-field digital mammography (FFDM) plus DBT with FFDM alone Performance indicators and characteristics of screen-detected and interval cancers were compared with two previous FFDM rounds 24,301 consenting women underwent FFDM + DBT screening over a 2-year period Results were compared with 59,877 FFDM examinations during prior rounds Addition of DBT resulted in a non-significant increase in sensitivity (762%, 378/496, vs 808%, 227/281, p = 0151) and a significant increase in specificity (964%, 57229/59381 vs 975%, 23427/24020, p < 001) Number of recalls per screen-detected cancer decreased from 67 (2530/378) to 36 (820/227) with DBT (p < 001) Cancer detection per 1000 women screened increased (63, 378/59877, vs 93, 227/24301, p < 001) Interval cancer rate per 1000 screens for FFDM + DBT remained similar to previous FFDM rounds (21, 51/24301 vs 20, 118/59877, p = 0734) Interval cancers post-DBT were comparable to prior rounds but significantly different in size, grade, and node status from cancers detected only using DBT 396% (19/48) of interval cancers had positive nodes compared with only 39% (2/51) of additional DBT-only-detected cancers DBT-supplemented screening resulted in significant increases in screen-detected cancers and specificity However, no significant change was observed in the rate, size, node status, or grade of interval cancers ClinicalTrialsgov: NCT01248546

Journal ArticleDOI
TL;DR: The short natural history of spontaneous canine invasive mammary carcinomas and high rate of cancer-related death allow for rapid termination of preclinical investigations, highlighting the similarities in cancer biology between both species.
Abstract: Dogs have been proposed as spontaneous animal models of human breast cancer, based on clinicopathologic similarities between canine and human mammary carcinomas. We hypothesized that a better knowledge of the natural history and prognostic factors of canine invasive mammary carcinomas would favor the design of preclinical trials using dogs as models of breast cancer. The 2-year outcome of 350 female dogs with spontaneous invasive mammary carcinoma was studied. The investigated prognostic factors included age at diagnosis, pathologic tumor size, pathologic nodal stage, lymphovascular invasion, histological grade, and expression of Estrogen Receptor alpha (ERα), Progesterone Receptor, Ki-67, Human Epidermal Growth Factor Receptor 2, basal cytokeratins 5/6, and Epidermal Growth Factor Receptor. Multivariate survival analyses were performed using the Cox proportional hazards model. The overall survival after mastectomy was 11 months. Within 1 year post mastectomy, 41.5% of dogs (145/350) died from their mammary carcinoma. By multivariate analysis, the significant prognostic factors for overall survival included a pathologic tumor size larger than 20 mm [HR 1.47 (95% confidence interval 1.15–1.89)], a positive nodal stage [pN+, HR 1.89 (1.43–2.48)], a histological grade III [HR 1.32 (1.02–1.69)], ERα negativity [HR 1.39 (1.01–1.89)], a high Ki-67 proliferation index [HR 1.32 (1.04–1.67)], and EGFR absence [HR 1.33 (1.04–1.69)]. The short natural history of spontaneous canine invasive mammary carcinomas and high rate of cancer-related death allow for rapid termination of preclinical investigations. The prognostic factors of invasive mammary carcinomas are remarkably similar in dogs and humans, highlighting the similarities in cancer biology between both species.

Journal ArticleDOI
TL;DR: Four plasma miRNAs and four serum miRNas from the miR-106a–363 cluster are identified and validated as promising novel biomarkers for the diagnosis of BC.
Abstract: Novel noninvasive biomarkers with high sensitivity and specificity for the diagnosis of breast cancer (BC) are urgently needed in clinics. The aim of this study was to explore whether miRNAs from the miR-106a–363 cluster can be detected in the circulation of BC patients and whether these miRNAs can serve as potential diagnostic biomarkers. The expression of 12 miRNAs from the miR-106a–363 cluster was evaluated using qRT-PCR in 400 plasma samples (from 200 BC patients and 200 healthy controls (HCs)) and 406 serum samples (from 204 BC patients and 202 HCs) via a three-phase study. The identified miRNAs were further examined in tissues (32 paired breast tissues), plasma exosomes (from 32 BC patients and 32 HCs), and serum exosomes (from 32 BC patients and 32 HCs). Upregulated levels of four plasma miRNAs (miR-106a-3p, miR-106a-5p, miR-20b-5p, and miR-92a-2-5p) and four serum miRNAs (miR-106a-5p, miR-19b-3p, miR-20b-5p, and miR-92a-3p) were identified and validated in BC. A plasma 4-miRNA panel and a serum 4-miRNA panel were constructed to discriminate BC patients from HCs. The areas under the receiver-operating characteristic curves of the plasma panel were 0.880, 0.902, and 0.858, and those of the serum panel were 0.910, 0.974, and 0.949 for the training, testing, and external validation phases, respectively. Two overlapping miRNAs (miR-106a-5p and miR-20b-5p) were consistently upregulated in BC tissues. Except for the expression of the plasma-derived exosomal miR-20b-5p, the expression patterns of exosomal miRNAs were concordant between plasma and serum, indicating the potential use of exosomal miRNAs as biomarkers. We identified four plasma miRNAs and four serum miRNAs from the miR-106a–363 cluster as promising novel biomarkers for the diagnosis of BC.

Journal ArticleDOI
TL;DR: Magnetic seeds are a feasible and safe method of breast lesion localization and can be accurately placed, demonstrate no migration in this feasibility study and are detectable in all sizes and depths of breast tissue.
Abstract: Wire localization has several disadvantages, notably wire migration and difficulty scheduling the procedure close to surgery. Radioactive seed localization overcomes these disadvantages, but implementation is limited due to radiation safety requirements. Magnetic seeds potentially offer the logistical benefits and transcutaneous detection equivalence of a radioactive seed, with easier implementation. This study was designed to evaluate the feasibility and safety of using magnetic seeds for breast lesion localization. A two-centre open-label cohort study to assess the feasibility and safety of magnetic seed (Magseed) localization of breast lesions. Magseeds were placed under radiological guidance into women having total mastectomy surgery. The primary outcome measure was seed migration distance. Secondary outcome measures included accuracy of placement, ease of transcutaneous detection, seed integrity and safety. Twenty-nine Magseeds were placed into the breasts of 28 patients under ultrasound guidance. There was no migration of the seeds between placement and surgery. Twenty-seven seeds were placed directly in the target lesion with the other seeds being 2 and 3 mm away. All seeds were detectable transcutaneously in all breast sizes and at all depths. There were no complications or safety issues. Magnetic seeds are a feasible and safe method of breast lesion localization. They can be accurately placed, demonstrate no migration in this feasibility study and are detectable in all sizes and depths of breast tissue. Now that safety and feasibility have been demonstrated, further clinical studies are required to evaluate the seed’s effectiveness in wide local excision surgery.

Journal ArticleDOI
TL;DR: Factors associated with the widening survival gap and non-equivalence between dnMBC and rM BC and decreased rMBC incidence warrant further study.
Abstract: Differences in de novo (dnMBC) and recurrent metastatic breast cancer (rMBC) presentation and survival over time have not been adequately described. A retrospective cohort study, 1990–2010, with follow up through 2015 of dnMBC patients (stage IV at diagnosis) and rMBC patients with subsequent distant metastatic recurrence (stage I–III initial diagnosis) [dnMBC = 247, rMBC = 911)]. Analysis included Chi squared tests of categorical variables, Kaplan–Meier survival estimates, and Cox proportional adjusted hazard ratios (HzR) and 95% confidence intervals (CI). Disease specific survival (DSS) was time from diagnosis or distant recurrence to BC death. Over time, 1990–1998, 1999–2004, and 2005–2010, dnMBC incidence was constant (3%) and rMBC incidence decreased [18% to 7% (p 1 distant metastases (HzR 1.39; 1.20, 1.62), and visceral dominant disease (HzR 1.22; 1.05, 1.43). After 1998, HER2-positive disease was associated with better DSS (HzR = 0.72, 95% CI 0.56, 0.93). Factors associated with the widening survival gap and non-equivalence between dnMBC and rMBC and decreased rMBC incidence warrant further study.

Journal ArticleDOI
TL;DR: The combination of alpelisib and T-DM1 is tolerable and demonstrates activity in trastuzumab-resistant HER2-positive MBC, suggesting that PIK3CA inhibition targets an important resistance pathway to anti-HER2 therapy.
Abstract: Activation of the phosphoinositide 3-kinase (PI3K) pathway is an important resistance mechanism to anti-HER2 therapies. This study aimed to assess the safety and activity of alpelisib (a PI3Kα isoform-specific inhibitor) with T-DM1 in trastuzumab- and taxane-resistant HER2-positive MBC. Patients with HER2-positive MBC that had progressed on trastuzumab-based therapy were treated with alpelisib daily and T-DM1 3.6 mg/kg every 3 weeks. The dose-limiting toxicity (DLT), maximum tolerated dose (MTD), adverse events, overall response rate (ORR), and clinical benefit rate (CBR = CR + PR + SD > 6 months) were assessed with descriptive statistics. Progression-free survival (PFS) was calculated by the Kaplan–Meier method. Seventeen patients were enrolled with a median of 3 prior therapies for metastatic disease. The DLT was a maculopapular rash and MTD was 250 mg alpelisib daily. The most frequently occurring toxicities included fatigue, rash, gastrointestinal side effects, thrombocytopenia, anemia, elevated liver enzymes, and hyperglycemia. Fourteen patients were evaluable for response with an ORR of 43%. In patients with prior treatment and progression on T-DM1 (n = 10), the ORR was 30%. The CBR was 71% in evaluable patients and 60% in those with prior T-DM1. The median PFS was 8.1 months. The combination of alpelisib and T-DM1 is tolerable and demonstrates activity in trastuzumab-resistant HER2-positive MBC. Furthermore, activity was observed in T-DM1-resistant disease. These data suggest that PIK3CA inhibition targets an important resistance pathway to anti-HER2 therapy, providing rationale for further study of PI3K inhibition in refractory HER2-positive MBC to validate these results.

Journal ArticleDOI
TL;DR: Several personal, social, and structural factors were identified that influenced AET adherence and persistence, including side effects, necessity beliefs, self-efficacy, the patient–healthcare provider relationship, social support, and continuity of follow-up care.
Abstract: Background Adjuvant endocrine therapy (AET) significantly reduces recurrence and mortality in women with breast cancer (BrCa). Despite the efficacy of AET in improving BrCa outcomes, up to 50% of women do not adhere to prescribed AET regimens. While numerous demographic and clinical predictors influence adherence and persistence, few studies have identified the patient-reported factors that influence AET adherence and persistence. Purpose The aim was to examine the patient-reported personal, social, and structural factors influencing BrCa survivors' adherence and persistence with AET. Methods An integrative review was undertaken wherein PubMed, Medline, CINAHL, Embase, and PsycINFO databases were searched using keyword descriptors and database subject headings. Inclusion criteria included quantitative or qualitative peer-reviewed studies written in English that assessed AET adherence and/or persistence through objective measurement or self-report and included patient-reported factors found to influence adherence and/or persistence. The data extracted from eligible studies were entered into a matrix, and systematically compared and iteratively analyzed using relational autonomy as an organizing theoretical framework. Results A total of 43 manuscripts (9 qualitative and 34 quantitative) were reviewed. Several personal, social, and structural factors were identified that influenced AET adherence and persistence, including side effects, necessity beliefs, self-efficacy, the patient-healthcare provider relationship, social support, and continuity of follow-up care. Conclusions An increasing number of studies have focused on identifying the patient-reported factors that influence AET adherence and persistence. This review highlights important personal, social, and structural factors that act as facilitators and barriers in adhering to and persisting with long-term AET. Acknowledging and addressing these factors is key to providing women with the care needed to improve suboptimal adherence and persistence.

Journal ArticleDOI
TL;DR: These results indicate that SES disparities in the receipt of treatments for incident breast cancer are both pervasive and substantial, and remained despite women’s geographic area of residence and extent of disease, suggesting important gaps in access to effective breast cancer care.
Abstract: Evidence suggests substantial disparities in breast cancer survival by socioeconomic status (SES). We examine the extent to which receipt of newer, less invasive, or more effective treatments—a plausible source of disparities in survival—varies by SES among elderly women with early-stage breast cancer. Multivariate regression analyses applied to 11,368 women (age 66–90 years) identified from SEER-Medicare as having invasive breast cancer diagnosed in 2006–2009. Socioeconomic status was defined based on Medicaid enrollment and level of poverty of the census tract of residence. All analyses controlled for demographic, clinical health status, spatial, and healthcare system characteristics. Poor and near-poor women were less likely than high SES women to receive sentinel lymph node biopsy and radiation after breast-conserving surgery (BCS). Poor women were also less likely than near-poor or high SES women to receive any axillary surgery and adjuvant chemotherapy. There were no significant differences in use of aromatase inhibitors (AI) between poor and high SES women. However, near-poor women who initiated hormonal therapy were more likely to rely exclusively on tamoxifen, and less likely to use the more expensive but more effective AI when compared to both poor and high SES women. Our results indicate that SES disparities in the receipt of treatments for incident breast cancer are both pervasive and substantial. These disparities remained despite women’s geographic area of residence and extent of disease, suggesting important gaps in access to effective breast cancer care.

Journal ArticleDOI
TL;DR: Ribociclib plus letrozole improved progression-free survival vs placebo plus let rozole and was well tolerated in postmenopausal women with HR+, HER2− de novo advanced breast cancer.
Abstract: Determine the efficacy and safety of first-line ribociclib plus letrozole in patients with de novo advanced breast cancer. Postmenopausal women with HR+ , HER2− advanced breast cancer and no prior systemic therapy for advanced disease were enrolled in the Phase III MONALEESA-2 trial (NCT01958021). Patients were randomized to ribociclib (600 mg/day; 3 weeks-on/1 week-off) plus letrozole (2.5 mg/day; continuous) or placebo plus letrozole until disease progression, unacceptable toxicity, death, or treatment discontinuation. The primary endpoint was investigator-assessed progression-free survival; predefined subgroup analysis evaluated progression-free survival in patients with de novo advanced breast cancer. Secondary endpoints included safety and overall response rate. Six hundred and sixty-eight patients were enrolled, of whom 227 patients (34%; ribociclib plus letrozole vs placebo plus letrozole arm: n = 114 vs. n = 113) presented with de novo advanced breast cancer. Median progression-free survival was not reached in the ribociclib plus letrozole arm versus 16.4 months in the placebo plus letrozole arm in patients with de novo advanced breast cancer (hazard ratio 0.45, 95% confidence interval 0.27–0.75). The most common Grade 3/4 adverse events were neutropenia and leukopenia; incidence rates were similar to those observed in the full MONALEESA-2 population. Ribociclib dose interruptions and reductions in patients with de novo disease occurred at similar frequencies to the overall study population. Ribociclib plus letrozole improved progression-free survival vs placebo plus letrozole and was well tolerated in postmenopausal women with HR+, HER2− de novo advanced breast cancer.

Journal ArticleDOI
TL;DR: The consensus conference on NSM and immediate reconstruction revealed substantial disagreement in expert panel opinion, which supports the need for a randomized trial to evaluate the safest and most efficacious reconstruction techniques.
Abstract: Indications for nipple-sparing mastectomy (NSM) have broadened to include the risk reducing setting and locally advanced tumors, which resulted in a dramatic increase in the use of NSM. The Oncoplastic Breast Consortium consensus conference on NSM and immediate reconstruction was held to address a variety of questions in clinical practice and research based on published evidence and expert panel opinion. The panel consisted of 44 breast surgeons from 14 countries across four continents with a background in gynecology, general or reconstructive surgery and a practice dedicated to breast cancer, as well as a patient advocate. Panelists presented evidence summaries relating to each topic for debate during the in-person consensus conference. The iterative process in question development, voting, and wording of the recommendations followed the modified Delphi methodology. Consensus recommendations were reached in 35, majority recommendations in 24, and no recommendations in the remaining 12 questions. The panel acknowledged the need for standardization of various aspects of NSM and immediate reconstruction. It endorsed several oncological contraindications to the preservation of the skin and nipple. Furthermore, it recommended inclusion of patients in prospective registries and routine assessment of patient-reported outcomes. Considerable heterogeneity in breast reconstruction practice became obvious during the conference. In case of conflicting or missing evidence to guide treatment, the consensus conference revealed substantial disagreement in expert panel opinion, which, among others, supports the need for a randomized trial to evaluate the safest and most efficacious reconstruction techniques.

Journal ArticleDOI
TL;DR: The evidence indicates that exercise can improve subjective and objective parameters in BCRL patients, with dynamic, moderate, and high-frequency exercise appearing to provide the most positive effects.
Abstract: The aim of this systematic review is to assess the effect of different types of exercise on breast cancer-related lymphedema (BCRL) in order to elucidate the role of exercise in this patient group. A systematic data search was performed using PubMed (December 2016). The review is focused on the rehabilitative aspect of BCRL and undertaken according to the PRISMA statement with Levels of Evidence (LoE) assessed. 11 randomized controlled trials (9 with LoE 1a and 2 with LoE 1b) that included 458 women with breast cancer in aftercare were included. The different types of exercise consisted of aqua lymph training, swimming, resistance exercise, yoga, aerobic, and gravity-resistive exercise. Four of the studies measured a significant reduction in BCRL status based on arm volume and seven studies reported significant subjective improvements. No study showed adverse effects of exercise on BCRL. The evidence indicates that exercise can improve subjective and objective parameters in BCRL patients, with dynamic, moderate, and high-frequency exercise appearing to provide the most positive effects.

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TL;DR: HR deficiency status is significantly associated with response to standard neoadjuvant chemotherapy in TNBC, consistent with the mechanisms of action of doxorubicin and cyclophosphamide as DNA damaging agents.
Abstract: Defects in the homologous recombination (HR) DNA repair pathway sensitize tumors to therapeutics that target this pathway. A significant proportion of triple-negative breast cancers (TNBC) carry HR defects. The HRD assay is highly associated with sensitivity to neoadjuvant platinum-based chemotherapy in TNBC. Standard chemotherapy consists of some combination of an anthracycline, cyclophosphamide, and taxane. This study assesses the association of HR deficiency status with response to standard neoadjuvant chemotherapy in TNBC or BRCA1/2 mutation-associated breast cancer. Tumor samples were retrospectively obtained from 45 TNBC patients and 2 BRCA1/2 mutant, hormone receptor-positive/HER2-negative breast cancer patients who received anthracycline- and/or taxane-based neoadjuvant chemotherapy at Stanford University or Cedars-Sinai Medical Centers. The HRD score and tumor BRCA1/2 mutation status were determined from baseline tumor biopsies. HR deficient tumors were those with a HRD score of ≥ 42 or a tumor BRCA1/2 mutation. Response was categorized by the residual cancer burden (RCB) index. HR deficient patients were more likely to achieve a pathologic complete response (pCR) compared with non-deficient patients (OR 13.06, CI 1.52–11.241, p = 0.0028). Among BRCA1/2 mutation wild-type patients, HR deficient patients were more likely to achieve a pCR (OR 16, 95% CI 1.65–160.41, p = 0.0041) compared with HR non-deficient patients. Further, HRD scores were highly concordant pre- and post-therapy (Spearman correlation > 99%). HR deficiency status is significantly associated with response to standard neoadjuvant chemotherapy in TNBC. This observation is consistent with the mechanisms of action of doxorubicin and cyclophosphamide as DNA damaging agents.

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TL;DR: The study showed that women of childbearing age, especially among Hispanic ethnicity with a recent history of pregnancy or high prolactin level and newly tender mass-like lesion, in addition to new focal asymmetry on mammogram and heterogeneous hypoechoic irregular-shaped mass on ultrasound exam, should raise concern for GM.
Abstract: To outline the demographics, clinical presentation, imaging features, and treatment modalities observed among a series of patients diagnosed with biopsy-proven granulomatous mastitis (GM). Following approval by institutional review board, retrospective chart review was performed on patients with biopsy-proven granulomatous mastitis at our institution in the period from January 2013 until October 2017. A total of 90 patients were identified: 87 women and 3 men. The mean age was 35 years, mostly women in their reproductive age. In our study, patients with GM were more likely to be Hispanic compared to the general population. Sixty-three percent of patients were within 5 years of previous pregnancy. Painful palpable mass-like lesion was the most common physical finding. Breast ultrasound (US) was performed in all patients, and most commonly showed a hypoechoic irregular-shaped mass. Mammography (MG) showed asymmetry or irregular mass as the main finding. Definitive diagnosis was obtained by imaging-guided core needle biopsies in 94.4%. Conservative management was preferred, and only one patient underwent surgery. Although clinical and radiological findings of patients with GM may mimic those of breast carcinoma, our study showed that women of childbearing age, especially among Hispanic ethnicity with a recent history of pregnancy or high prolactin level and newly tender mass-like lesion, in addition to new focal asymmetry on mammogram and heterogeneous hypoechoic irregular-shaped mass on ultrasound exam, should raise concern for GM. Non-invasive approach and clinical follow-up were the preferred treatment method.

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TL;DR: In early-stage TNBC, nodal involvement, TILs, and receipt of adjuvant chemotherapy were independently associated with IDFS and OS and remained prognostic and the risk of recurrence or death was substantial, even for T1N0 disease.
Abstract: Given its high recurrence risk, guidelines recommend systemic therapy for most patients with early-stage triple-negative breast cancer (TNBC). While some clinicopathologic factors and tumor-infiltrating lymphocytes (TILs) are known to be prognostic in patients receiving chemotherapy, their prognostic implications in systemically untreated patients remain unknown. From a cohort of 9982 women with surgically treated non-metastatic breast cancer, all patients with clinically reported ER-negative/borderline (≤10%) disease were selected for central assessment of ER/PR/HER2, histopathology, Ki-67, and TILs. The impact of these parameters on invasive disease-free survival (IDFS) and overall survival (OS) was assessed using Cox proportional hazards models. Six hundred five patients met the criteria for TNBC (ER/PR 15% (75%). Histologically, 70% were invasive carcinoma of no special type, 16% medullary, 8% metaplastic, and 6% apocrine. The median stromal TIL content was 20%. Four hundred twenty-three (70%) patients received adjuvant chemotherapy. Median OS follow-up was 10.6 years. On multivariate analysis, only higher nodal stage, lower TILs, and the absence of adjuvant chemotherapy were associated with worse IDFS and OS. Among systemically untreated patients (n = 182), the 5-year IDFS was 69.9% (95% CI 60.7–80.5) [T1a: 82.5% (95% CI 62.8–100), T1b: 67.5% (95% CI 51.9–87.8) and T1c: 67.3% (95% CI 54.9–82.6)], compared to 77.8% (95% CI 68.3–83.6) for systemically treated T1N0. Nodal stage and TILs remained strongly associated with outcomes. In early-stage TNBC, nodal involvement, TILs, and receipt of adjuvant chemotherapy were independently associated with IDFS and OS. In systemically untreated TNBC, TILs remained prognostic and the risk of recurrence or death was substantial, even for T1N0 disease.

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TL;DR: Sixteen weeks of RT-HIIT significantly improved muscle strength and reduced pain sensitivity and both exercise programs were equally efficient in preventing increases in body mass and in preventing declines in cardiorespiratory fitness.
Abstract: Advanced therapeutic strategies are often accompanied by significant adverse effects, which warrant equally progressive countermeasures. Physical exercise has proven an effective intervention to improve physical function and reduce fatigue in patients undergoing chemotherapy. Effects of high-intensity interval training (HIIT) in this population are not well established although HIIT has proven effective in other clinical populations. The aim of the OptiTrain trial was to examine the effects of concurrent resistance and high-intensity interval training (RT-HIIT) or concurrent moderate-intensity aerobic and high-intensity interval training (AT-HIIT), to usual care (UC) on pain sensitivity and physiological outcomes in patients with breast cancer during chemotherapy. Two hundred and forty women were randomized to 16 weeks of RT-HIIT, AT-HIIT, or UC. Outcomes: cardiorespiratory fitness, muscle strength, body mass, hemoglobin levels, and pressure-pain threshold. Pre- to post-intervention, RT-HIIT (ES = 0.41) and AT-HIIT (ES = 0.42) prevented the reduced cardiorespiratory fitness found with UC. Handgrip strength (surgery side: RT-HIIT vs. UC: ES = 0.41, RT-HIIT vs. AT-HIIT: ES = 0.28; non-surgery side: RT-HIIT vs. UC: ES = 0.35, RT-HIIT vs. AT-HIIT: ES = 0.22) and lower-limb muscle strength (RT-HIIT vs. UC: ES = 0.66, RT-HIIT vs. AT-HIIT: ES = 0.23) were significantly improved in the RT-HIIT. Increases in body mass were smaller in RT-HIIT (ES = − 0.16) and AT-HIIT (ES = − 0.16) versus UC. RT-HIIT reported higher pressure-pain thresholds than UC (trapezius: ES = 0.46, gluteus: ES = 0.53) and AT-HIIT (trapezius: ES = 0.30). Sixteen weeks of RT-HIIT significantly improved muscle strength and reduced pain sensitivity. Both exercise programs were well tolerated and were equally efficient in preventing increases in body mass and in preventing declines in cardiorespiratory fitness. These results highlight the importance of implementing a combination of resistance and high-intensity interval training during chemotherapy for women with breast cancer.

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TL;DR: H19 regulates CSC and is associated with poor prognosis in breast cancer patients, particularly in triple-negative subtype, and in-vitro analysis showed that suppression of H19 using siRNA reduces sphere formation capacity in both HCC1934 and iCSCL10A cell lines.
Abstract: Aldehyde dehydrogenase1 (ALDH1) is widely accepted as a stem cell marker for normal breast as well as in breast cancer. Although the clinical impact of ALDH1 was observed in our previous study, we do not know how ALDH1 affects stem cell features resulting in worsening of prognosis in breast cancer. The purpose of this study is to explore ALDH1-related gene and its function on cancer stem cell (CSC). In five cases of ALDH1-positive triple-negative breast cancer, mRNA expression profile was compared between ALDH1-positive and ALDH1-negative cells by Affymetrix microarray analysis after microdissection. Among the genes modulated in ALDH1-positive cells, we focused on H19, which encodes a long non-coding RNA, in this study. An in-vitro study was conducted with H19 siRNA in HCC1934 and iCSCL10A cell lines. The association of H19 with prognosis was examined in 180 breast cancer cases. Network analysis revealed the existence of five genes related with H19, including miR-103, miR-107, let-7, miR-29b-1, and Trx. In-vitro analysis showed that suppression of H19 using siRNA reduces sphere formation capacity in both HCC1934 and iCSCL10A cell lines. In clinical studies, H19 expression was associated with hormone negativity, tumor size, and nodal status. Patients with H19 expression had significantly poor disease-free survival (DFS) (26.3 vs. 64.8% at 5 years, p = 0.001) and overall survival (OS) (28.9 vs. 68.3% at 5 years, p = 0.004). The effect of H19 expression on prognosis was the most significant in triple-negative breast cancer compared to that in other subtypes (20.0 vs. 65.4% at 5 years DFS, p = 0.012, 20.0 vs. 69.2% at 5 years OS, p = 0.016). This study indicated that H19 was associated with stem cell phenotype in ALDH1-positive breast cancer. H19 regulates CSC and is associated with poor prognosis in breast cancer patients, particularly in triple-negative subtype.

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TL;DR: The data show that MCP-1 is upregulated in TNBC cell lines both transcriptionally as well as in secreted protein levels compared to ER-positive luminal cell line, MCF-7, which suggests that M CP-1-CCR2 axis may regulate invasiveness via the MAP Kinase pathway.
Abstract: Triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer that lacks ER/PR and HER2 receptors. Hence, there is urgency in developing new or novel therapeutic strategies for treatment of TNBC. Our study shows that the Monocyte Chemoattractant Protein-1 (MCP-1) is a marker associated with TNBC and may play a key role in TNBC disease progression. ELISA method was used to measure secreted MCP-1, and mRNA levels were determined by Real-time PCR in numerous cancer cell lines, representing various breast cancer subtypes. Cellular invasiveness was determined by Boyden chamber assay. Our data show that MCP-1 is upregulated in TNBC cell lines both transcriptionally as well as in secreted protein levels compared to ER-positive luminal cell line, MCF-7. Breast cancer patients, with Basal or Claudin-low subtypes, also showed high expression of MCP-1. MCP-1 treatment induced cell invasion in various breast cancer cell types, without affecting cell proliferation. Small molecule antagonists against Chemokine Receptor 2 (CCR2), cognate receptor for MCP-1 as well as the MAP kinase pathway inhibitor U0126 negatively affected MCP-1 induced MCF-7 cell invasion. This suggests that MCP-1-CCR2 axis may regulate invasiveness via the MAP Kinase pathway. Knocking down MCP-1 decreased cell invasion in TNBC cell line BT-549, along with downregulation of key epithelial to mesenchymal transition markers, N-cadherin and Vimentin. Our study suggests that MCP-1 mediated pathways could be potential therapeutic targets for the treatment of TNBC, and could reduce cancer health disparities.

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TL;DR: EVs isolated from the HCC1806 TNBC cells are capable of inducing proliferation and drug resistance on the non-tumorigenic MCF10A breast cells, potentially mediated by changes in genes and miRNAs expression associated with cell proliferation, apoptosis, invasion, and migration.
Abstract: Triple-negative breast cancer (TNBC), an aggressive breast cancer subtype, is genetically heterogeneous which challenges the identification of clinically effective molecular makers. Extracellular vesicles (EVs) are key players in the intercellular signaling communication and have been shown to be involved in tumorigenesis. The main goal of this study was to evaluate the role and mechanisms of EVs derived from TNBC cells in modulating proliferation and cytotoxicity to chemotherapeutic agents in non-tumorigenic breast cells (MCF10A). EVs were isolated from TNBC cell lines and characterized by nanoparticle tracking analysis, Western blot, and transmission electron microscopy. MCF10A cells were treated with the isolated EVs and evaluated for cell proliferation and cytotoxicity to Docetaxel and Doxorubicin by the MTT and MTS assays, respectively. Gene and miRNA expression profiling was performed in the treated cells to determine expression changes that may be caused by EVs treatment. MCF10A cells treated with HCC1806-EVs (MCF10A/HCC1806-EVs) showed a significant increase in cell proliferation and resistance to the therapeutic agents tested. No significant effects were observed in the MCF10A cells treated with EVs derived from MDA-MB-231 cells. Gene and miRNA expression profiling revealed 138 genes and 70 miRNAs significantly differentially expressed among the MCF10A/HCC1806-EVs and the untreated MCF10A cells, affecting mostly the PI3K/AKT, MAPK, and HIF1A pathways. EVs isolated from the HCC1806 TNBC cells are capable of inducing proliferation and drug resistance on the non-tumorigenic MCF10A breast cells, potentially mediated by changes in genes and miRNAs expression associated with cell proliferation, apoptosis, invasion, and migration.

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TL;DR: PI3K pathway activation is associated with resistance to lapatinib and trastuzumab in breast cancers, without chemotherapy and further studies are warranted to investigate how to use these biomarkers to identify upfront patients who may respond to anti-HER2 alone,Without chemotherapy.
Abstract: Aberrant activation of the PI3K pathway has been implicated in resistance to HER2-targeted therapy, but results of clinical trials are confounded by the co-administration of chemotherapy. We investigated the effect of perturbations of this pathway in breast cancers from patients treated with neoadjuvant anti-HER2-targeted therapy without chemotherapy. Baseline tumor samples from patients with HER2-positive breast cancer enrolled in TBCRC006 (NCT00548184), a 12-week neoadjuvant clinical trial with lapatinib plus trastuzumab [plus endocrine therapy for estrogen receptor (ER)-positive tumors], were assessed for PTEN status by immunohistochemistry and PIK3CA mutations by sequencing. Results were correlated with pathologic complete response (pCR). Of 64 evaluable patients, PTEN immunohistochemistry and PIK3CA mutation analysis were performed for 59 and 46 patients, respectively. PTEN status (dichotomized by H-score median) was correlated with pCR (32% in high PTEN vs. 9% in low PTEN, p = 0.04). PIK3CA mutations were identified in 14/46 tumors at baseline (30%) and did not correlate with ER or PTEN status. One patient whose tumor harbored a PIK3CA mutation achieved pCR (p = 0.14). When considered together (43 cases), 1/25 cases (4%) with a PIK3CA mutation and/or low PTEN expression levels had a pCR compared to 7/18 cases (39%) with wild-type PI3KCA and high PTEN expression levels (p = 0.006). PI3K pathway activation is associated with resistance to lapatinib and trastuzumab in breast cancers, without chemotherapy. Further studies are warranted to investigate how to use these biomarkers to identify upfront patients who may respond to anti-HER2 alone, without chemotherapy.

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TL;DR: Double-negative CMCs largely predominated, were much more prevalent than in human beings, and showed an aggressive natural behavior after mastectomy, and Dogs are thus potent valuable spontaneous models to test new therapeutic strategies for this particular subtype of breast cancer.
Abstract: Relevant animal models of human breast cancer are currently needed, especially for the aggressive triple-negative breast cancer subtype. Recent studies and our results (Part 1) indicate that spontaneous canine invasive mammary carcinomas (CMCs) resemble human breast cancer by clinics and pathology as well as behavior and prognostic indicators. We hypothesized that the current molecular classifications of human breast cancer, used for therapeutic decision, could be relevant to dogs. Three hundred and fifty female dogs with spontaneous CMC and a 2-year follow-up were retrospectively included. By immunohistochemistry, CMCs were classified according to Nielsen (Clin Cancer Res 10:5367–5374, 2004) and Blows (PlosOne doi: 10.1371/journal.pmed.1000279, 2010) into the subtypes of human breast cancer. Four immunophenotypes were defined either according to Nielsen classification (luminal A 14.3%, luminal B 9.4%, triple-negative basal-like 58.6%, and triple-negative nonbasal-like 17.7% CMCs); or to Blows classification (luminal 1−: 11.4%, luminal 1+: 12.3%, Core basal phenotype: 58.6%, and five-negative phenotype: 17.7%). No HER2-overexpressing CMC as defined by a 3 + immunohistochemical score was observed in our cohort. By univariate and multivariate analyses, both immunophenotypical classifications applied to CMCs showed strong prognostic significance: luminal A or luminal 1+ CMCs showed a significantly longer disease-free interval (HR = 0.46), Overall (HR = 0.47), and Specific Survival (HR = 0.56) compared to triple-negative carcinomas, after adjustment for stage. In our cohort, triple-negative CMCs largely predominated (76%), were much more prevalent than in human beings, and showed an aggressive natural behavior after mastectomy. Dogs are thus potent valuable spontaneous models to test new therapeutic strategies for this particular subtype of breast cancer.