The purpose of this study was to classify breast carcinomas based on variations in gene expression patterns derived from cDNA microarrays and to correlate tumor characteristics to clinical outcome. A total of 85 cDNA microarray experiments representing 78 cancers, three fibroadenomas, and four normal breast tissues were analyzed by hierarchical clustering. As reported previously, the cancers could be classified into a basal epithelial-like group, an ERBB2-overexpressing group and a normal breast-like group based on variations in gene expression. A novel finding was that the previously characterized luminal epithelial/estrogen receptor-positive group could be divided into at least two subgroups, each with a distinctive expression profile. These subtypes proved to be reasonably robust by clustering using two different gene sets: first, a set of 456 cDNA clones previously selected to reflect intrinsic properties of the tumors and, second, a gene set that highly correlated with patient outcome. Survival analyses on a subcohort of patients with locally advanced breast cancer uniformly treated in a prospective study showed significantly different outcomes for the patients belonging to the various groups, including a poor prognosis for the basal-like subtype and a significant difference in outcome for the two estrogen receptor-positive groups.

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Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications

Breast cancer patients with the same stage of disease can have markedly different treatment responses and overall outcome. The strongest predictors for metastases (for example, lymph node status and histological grade) fail to classify accurately breast tumours according to their clinical behaviour. Chemotherapy or hormonal therapy reduces the risk of distant metastases by approximately one-third; however, 70-80% of patients receiving this treatment would have survived without it. None of the signatures of breast cancer gene expression reported to date allow for patient-tailored therapy strategies. Here we used DNA microarray analysis on primary breast tumours of 117 young patients, and applied supervised classification to identify a gene expression signature strongly predictive of a short interval to distant metastases ('poor prognosis' signature) in patients without tumour cells in local lymph nodes at diagnosis (lymph node negative). In addition, we established a signature that identifies tumours of BRCA1 carriers. The poor prognosis signature consists of genes regulating cell cycle, invasion, metastasis and angiogenesis. This gene expression profile will outperform all currently used clinical parameters in predicting disease outcome. Our findings provide a strategy to select patients who would benefit from adjuvant therapy.

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Gene expression profiling predicts clinical outcome of breast cancer

Background A more accurate means of prognostication in breast cancer will improve the selection of patients for adjuvant systemic therapy. Methods Using microarray analysis to evaluate our previously established 70-gene prognosis profile, we classified a series of 295 consecutive patients with primary breast carcinomas as having a gene-expression signature associated with either a poor prognosis or a good prognosis. All patients had stage I or II breast cancer and were younger than 53 years old; 151 had lymph-node–negative disease, and 144 had lymph-node–positive disease. We evaluated the predictive power of the prognosis profile using univariable and multivariable statistical analyses. Results Among the 295 patients, 180 had a poor-prognosis signature and 115 had a good-prognosis signature, and the mean (±SE) overall 10-year survival rates were 54.6±4.4 percent and 94.5±2.6 percent, respectively. At 10 years, the probability of remaining free of distant metastases was 50.6±4.5 percent in the group with a...

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A Gene-Expression Signature as a Predictor of Survival in Breast Cancer

background The likelihood of distant recurrence in patients with breast cancer who have no involved lymph nodes and estrogen-receptor–positive tumors is poorly defined by clinical and histopathological measures. methods We tested whether the results of a reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assay of 21 prospectively selected genes in paraffin-embedded tumor tissue would correlate with the likelihood of distant recurrence in patients with node-negative, tamoxifen-treated breast cancer who were enrolled in the National Surgical Adjuvant Breast and Bowel Project clinical trial B-14. The levels of expression of 16 cancerrelated genes and 5 reference genes were used in a prospectively defined algorithm to calculate a recurrence score and to determine a risk group (low, intermediate, or high) for each patient. results Adequate RT-PCR profiles were obtained in 668 of 675 tumor blocks. The proportions of patients categorized as having a low, intermediate, or high risk by the RT-PCR assay were 51, 22, and 27 percent, respectively. The Kaplan–Meier estimates of the rates of distant recurrence at 10 years in the low-risk, intermediate-risk, and high-risk groups were 6.8 percent (95 percent confidence interval, 4.0 to 9.6), 14.3 percent (95 percent confidence interval, 8.3 to 20.3), and 30.5 percent (95 percent confidence interval, 23.6 to 37.4). The rate in the low-risk group was significantly lower than that in the high-risk group (P<0.001). In a multivariate Cox model, the recurrence score provided significant predictive power that was independent of age and tumor size (P<0.001). The recurrence score was also predictive of overall survival (P<0.001) and could be used as a continuous function to predict distant recurrence in individual patients. conclusions The recurrence score has been validated as quantifying the likelihood of distant recurrence in tamoxifen-treated patients with node-negative, estrogen-receptor–positive breast cancer.

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A Multigene Assay to Predict Recurrence of Tamoxifen-Treated, Node-Negative Breast Cancer

Morphological assessment of the degree of differentiation has been shown in numerous studies to provide useful prognostic information in breast cancer, but until recently histological grading has not been accepted as a routine procedure, mainly because of perceived problems with reproducibility and consistency. In the Nottingham/Tenovus Primary Breast Cancer Study the most commonly used method, described by Bloom & Richardson, has been modified in order to make the criteria more objective. The revised technique involves semiquantitative evaluation of three morphological features--the percentage of tubule formation, the degree of nuclear pleomorphism and an accurate mitotic count using a defined field area. A numerical scoring system is used and the overall grade is derived from a summation of individual scores for the three variables: three grades of differentiation are used. Since 1973, over 2200 patients with primary operable breast cancer have been entered into a study of multiple prognostic factors. Histological grade, assessed in 1831 patients, shows a very strong correlation with prognosis; patients with grade I tumours have a significantly better survival than those with grade II and III tumours (P less than 0.0001). These results demonstrate that this method for histological grading provides important prognostic information and, if the grading protocol is followed consistently, reproducible results can be obtained. Histological grade forms part of the multifactorial Nottingham prognostic index, together with tumour size and lymph node stage, which is used to stratify individual patients for appropriate therapy.

Pathological prognostic factors in breast cancer. I. The value of histological grade in breast cancer: experience from a large study with long-term follow-up.

PURPOSEWe assessed the prognostic importance of the level of thymidylate synthase (TS) expression in patients with primary rectal cancer and whether, for Dukes' B and C cancer patients, the benefit of chemotherapy was associated with TS expression.PATIENTS AND METHODSThe level of TS expression in the primary rectal cancers of 294 of 801 patients enrolled on protocol R-01 of the National Surgical Adjuvant Breast and Bowel Project (NSABP) was immunohistochemically assessed with the monoclonal antibody TS 106.RESULTSForty-nine percent of patients whose tumors had low TS levels (n = 91) were disease free at 5 years compared with 27% of patients with high levels of TS (n = 203; P < .01). Moreover, 60% of patients with low TS levels were alive after 5 years compared with 40% of patients with high TS levels (P < .01). The level of TS protein was significantly associated with Dukes' stage (P < .01); patients with a more advanced Dukes' stage had a significantly higher level of TS. The level of TS expression remai...

The role of thymidylate synthase expression in prognosis and outcome of adjuvant chemotherapy in patients with rectal cancer.

Purpose Locoregional failure after breast-conserving surgery is associated with increased risk of distant disease and death. The magnitude of this risk in patients receiving chemotherapy has not been adequately characterized. Patients and Methods Our study population included 2,669 women randomly assigned onto five National Surgical Adjuvant Breast and Bowel Project node-positive protocols (B-15, B-16, B-18, B-22, and B-25), who were treated with lumpectomy, whole-breast irradiation, and adjuvant systemic therapy. Cumulative incidences of ipsilateral breast tumor recurrence (IBTR) and other locoregional recurrence (oLRR) were calculated. Kaplan-Meier curves were used to estimate distant–disease-free survival (DDFS) and overall survival (OS) after IBTR or oLRR. Cox models were used to model survival using clinical and pathologic factors jointly with IBTR or oLRR as time-varying predictors. Results Four hundred twenty-four patients (15.9%) experienced locoregional failure; 259 (9.7%) experienced IBTR, and 1...

https://ascopubs.org/doi/pdf/10.1200/jco.2005.04.3273

Prognosis After Ipsilateral Breast Tumor Recurrence and Locoregional Recurrences in Five National Surgical Adjuvant Breast and Bowel Project Node-Positive Adjuvant Breast Cancer Trials

This study correlates the disease-free survival (DFS), distant disease-free survival (DDFS), and survival (S) of 1,157 histologically node negative breast cancer patients with the estrogen and/or progesterone receptor (ER, PR) and with the nuclear or histologic grade (NG, HG) of their tumors. All were treated by operation without systemic adjuvant therapy. The DFS, DDFS, and S were significantly greater (P = .005, .004, less than .001) in patients with ER positive than ER negative tumors but the magnitude of the differences after 5 years of follow-up was slight (8% in both DFS and DDFS and 10% in S). Differences of that magnitude are insufficient to discriminate clearly between patients who should or should not receive systemic therapy. As with ER, there were outcome differences in favor of PR positive tumors but only in S was the difference significant (8% at 5 years; P = .002). When combined with ER, PR made no independent contribution in the outcome prediction. Regression analysis indicated that NG was...

Relative worth of estrogen or progesterone receptor and pathologic characteristics of differentiation as indicators of prognosis in node negative breast cancer patients: findings from National Surgical Adjuvant Breast and Bowel Project Protocol B-06.

The accuracy of clinical nodal staging and of limited axillary dissection as a determinant of histologic nodal status in carcinoma of the breast.

Findings from this study using a transplantable C3H mammary tumor failed to indicate interaction relative to growth parameters between two foci present in the same host. Whether they were growing alone or in the presence of a second focus, tumor growth rates were similar until the combined mass of multiple tumors approached that which was incompatible with survival. Only then was a difference in growth observed. Cytokinetic parameters, i.e. , labeling index, primer-dependent DNA polymerase index or growth fraction, DNA synthesis time, tumor doubling time, and cell cycle time, were also similar whether tumors grew alone or in the presence of a second focus. Following removal of a tumor, changes were observed within 24 hr in the kinetics of the residual focus. There was an increase in labeling index (duration ⋍ 10 days) and primer-dependent DNA polymerase index with a decrease in the tumor doubling time. Minimal change was noted in DNA synthesis time and cell cycle time. The kinetic changes observed were reflected in a measurable increase in tumor size ⋍ a week following tumor removal. Absence of an alteration in DNA synthesis time and cell cycle time indicates that the increase in tumor growth was probably due to a conversion of noncycling cells in Go phase into proliferation. Relationship of the findings to the use of adjuvant chemotherapy is considered.

https://cancerres.aacrjournals.org/content/canres/39/10/3861.full.pdf

Bernard Fisher

Papers

The role of thymidylate synthase expression in prognosis and outcome of adjuvant chemotherapy in patients with rectal cancer.

Prognosis After Ipsilateral Breast Tumor Recurrence and Locoregional Recurrences in Five National Surgical Adjuvant Breast and Bowel Project Node-Positive Adjuvant Breast Cancer Trials

Relative worth of estrogen or progesterone receptor and pathologic characteristics of differentiation as indicators of prognosis in node negative breast cancer patients: findings from National Surgical Adjuvant Breast and Bowel Project Protocol B-06.

The accuracy of clinical nodal staging and of limited axillary dissection as a determinant of histologic nodal status in carcinoma of the breast.

Effect of Surgical Removal on the Growth and Kinetics of Residual Tumor