Triple-negative breast cancer (TNBC), a specific subtype of breast cancer that does not express estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER-2), has clinical features that include high invasiveness, high metastatic potential, proneness to relapse, and poor prognosis. Because TNBC tumors lack ER, PR, and HER2 expression, they are not sensitive to endocrine therapy or HER2 treatment, and standardized TNBC treatment regimens are still lacking. Therefore, development of new TNBC treatment strategies has become an urgent clinical need. By summarizing existing treatment regimens, therapeutic drugs, and their efficacy for different TNBC subtypes and reviewing some new preclinical studies and targeted treatment regimens for TNBC, this paper aims to provide new ideas for TNBC treatment.

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Triple-negative breast cancer molecular subtyping and treatment progress.

In this study, we evaluated the ability of radiomic textural analysis of intratumoral and peritumoral regions on pretreatment breast cancer dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to predict pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) A total of 117 patients who had received NAC were retrospectively analyzed Within the intratumoral and peritumoral regions of T1-weighted contrast-enhanced MRI scans, a total of 99 radiomic textural features were computed at multiple phases Feature selection was used to identify a set of top pCR-associated features from within a training set (n = 78), which were then used to train multiple machine learning classifiers to predict the likelihood of pCR for a given patient Classifiers were then independently tested on 39 patients Experiments were repeated separately among hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+, HER2−) and triple-negative or HER2+ (TN/HER2+) tumors via threefold cross-validation to determine whether receptor status-specific analysis could improve classification performance Among all patients, a combined intratumoral and peritumoral radiomic feature set yielded a maximum AUC of 078 ± 0030 within the training set and 074 within the independent testing set using a diagonal linear discriminant analysis (DLDA) classifier Receptor status-specific feature discovery and classification enabled improved prediction of pCR, yielding maximum AUCs of 083 ± 0025 within the HR+, HER2− group using DLDA and 093 ± 0018 within the TN/HER2+ group using a naive Bayes classifier In HR+, HER2− breast cancers, non-pCR was characterized by elevated peritumoral heterogeneity during initial contrast enhancement However, TN/HER2+ tumors were best characterized by a speckled enhancement pattern within the peritumoral region of nonresponders Radiomic features were found to strongly predict pCR independent of choice of classifier, suggesting their robustness as response predictors Through a combined intratumoral and peritumoral radiomics approach, we could successfully predict pCR to NAC from pretreatment breast DCE-MRI, both with and without a priori knowledge of receptor status Further, our findings suggest that the radiomic features most predictive of response vary across different receptor subtypes

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Intratumoral and peritumoral radiomics for the pretreatment prediction of pathological complete response to neoadjuvant chemotherapy based on breast DCE-MRI

Genetic abnormalities in the DNA repair genes BRCA1 and BRCA2 predispose to hereditary breast and ovarian cancer (HBOC). However, only approximately 25% of cases of HBOC can be ascribed to BRCA1 and BRCA2 mutations. Recently, exome sequencing has uncovered substantial locus heterogeneity among affected families without BRCA1 or BRCA2 mutations. The new pathogenic variants are rare, posing challenges to estimation of risk attribution through patient cohorts. In this Review article, we examine HBOC genes, focusing on their role in genome maintenance, the possibilities for functional testing of putative causal variants and the clinical application of new HBOC genes in cancer risk management and treatment decision-making.

Hereditary breast and ovarian cancer: new genes in confined pathways

Summary Background HER2-positive breast cancer consists of four intrinsic molecular subtypes—luminal A, luminal B, HER2-enriched, and basal-like—and a normal-like subtype, with the HER2-enriched subtype having the highest activation of the EGFR–HER2 pathway. We aimed to test the hypothesis that patients with the HER2-enriched subtype benefit the most from dual HER2 blockade. Methods PAMELA is an open-label, single-group, phase 2 trial done in 19 hospitals in Spain. We recruited female patients aged at least 18 years with previously untreated, centrally confirmed HER2-positive, stage I–IIIA invasive breast cancer regardless of hormone receptor status. Patients were given lapatinib (1000 mg per day orally) and trastuzumab (loading dose of 8 mg/kg, followed by 6 mg/kg every 3 weeks intravenously) for 18 weeks; hormone receptor-positive patients were additionally given letrozole (2·5 mg per day orally; if menopausal) or tamoxifen (20 mg per day orally; if premenopausal). Surgery was done 1–3 weeks after the last dose of study treatment. Intrinsic molecular subtypes of tumour biopsy samples taken at baseline (day 0) and day 14 were determined with the PAM50 predictor. The primary outcome was the ability of the HER2-enriched subtype to predict pathological complete response at the time of surgery. The primary outcome was assessed in the evaluable population (ie, all patients who had initial tumour biopsy samples available and who underwent definitive surgery) and safety was assessed in all patients who received at least one part of study treatment. This study is registered with ClinicalTrials.gov, number NCT01973660, and is completed. Findings Between Oct 28, 2013, and Nov 26, 2015, we recruited 151 patients, of whom 14 (9%) discontinued treatment and 137 (91%) completed treatment as planned. At baseline, most patients had the HER2-enriched subtype (101 [67%]), followed by luminal A (22 [15%]), luminal B (16 [11%]), basal-like (nine [6%]), and normal-like (three [2%]) subtypes. At the time of surgery, 46 (30%, 95% CI 23–39) of 151 patients had pathological complete response in the breast. 41 (41%, 31–51) of 101 patients with the HER2-enriched subtype and five (10%, 4–23) of 50 patients with non-HER2-enriched subtypes achieved pathological complete response at the time of surgery (odds ratio 6·2, 95% CI 2·3–16·8; p=0·0004). Interpretation The HER2-enriched subtype can identify patients with HER2-positive breast cancer who are likely to benefit from dual HER2 blockade therapies. Funding GlaxoSmithKline, Susan Komen Foundation, CERCA Programme—Generalitat de Catalunya, Banco Bilbao Vizcaya Argentaria Foundation, Pas a Pas, and the Breast Cancer Research Foundation.

https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(17)30021-9.pdf

HER2-enriched subtype as a predictor of pathological complete response following trastuzumab and lapatinib without chemotherapy in early-stage HER2-positive breast cancer (PAMELA): an open-label, single-group, multicentre, phase 2 trial

Wnt signaling regulates a variety of cellular processes, including cell fate, differentiation, proliferation and stem cell pluripotency. Aberrant Wnt signaling is a hallmark of many cancers. An aggressive subtype of breast cancer, known as triple-negative breast cancer (TNBC), demonstrates dysregulation in canonical and non-canonical Wnt signaling. In this review, we summarize regulators of canonical and non-canonical Wnt signaling, as well as Wnt signaling dysfunction that mediates the progression of TNBC. We review the complex molecular nature of TNBC and the emerging therapies that are currently under investigation for the treatment of this disease.

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Marc Díez

Papers

Clinical implications of the intrinsic molecular subtypes of breast cancer.