Breast Cancer Prognosis Determined by Gene Expression Profiling: A Quantitative Reverse Transcriptase Polymerase Chain Reaction Study

We sought to reproduce with quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) the results obtained with a 70-gene expression profile that has been described previously in breast cancer. Frozen breast cancer samples from patients who were operated on were used to isolate tumor RNA. Ninety-six patients with stage I to II disease were included. Median age was 57 years (range, 27 to 80 years). Forty-eight patients had lymph node-negative and 48 lymph node-positive disease. qRT-PCR amplifications were performed and the results were correlated with clinical data. After a minimum follow-up of 5 years, 25 patients had a relapse. The gene profile divided patients into two groups with poor and good prognosis. Significant differences with regard to grade of differentiation, size and hormone receptors were seen between the two groups. The gene profile was significantly associated with relapse-free survival and overall survival in the whole group of 96 patients. Multivariate analysis showed that only lymph node status and gene profile were significantly correlated to overall survival. qRT-PCR reproduced the results obtained with microarrays for a prognostic gene profile in women with early-stage breast cancer.