A 5-gene signature predicts outcome in women with hormone receptor-negative early breast cancer treated with chemoterapy.

Hormone-receptor negative (HR-) breast cancer accounts for approximately one third of all breast tumors and has a worse prognosis compared with hormone receptor-positive disease. Their unfavorable outcome and the lack of hormonal receptors determine the use of adjuvant chemotherapy as part of the standard treatment for these tumors. However, a significant proportion of patients relapse after receiving adjuvant chemotherapy. Classical prognostic factors such as tumor size, lymph node status and grade of differentiation do not suffice to identify patients with a higher risk of relapse. In the last decade, gene profiling has allowed the description of signatures with prognostic value in hormone receptor-positive tumors, but similar information is scarce in HR- disease. Reliable identification of poor-prognosis patients would be important to offer participation in clinical trials with new drugs and to modify follow-up schedules. In this study, we assessed gene expression with quantitative polymerase-chain reaction (RT-qPCR) in HR- early stage breast cancer. RNA was isolated from formalin-fixed paraffin-embedded (FFPE) tissue. Our purpose was to identify a gene signature related to outcome. RNA expression profiles from 65 ffpe tumor samples from patients diagnosed of invasive ductal carcinoma of the breast and at least 5 years of follow-up were determined with the goal of developing a gene expression-based model predictive of recurrence