Expression signature of ten genes predicts the survival of patients with estrogen receptor positive-breast cancer that were treated with tamoxifen.

Although tamoxifen is the most frequently used drug for the treatment of estrogen receptor positive (ER+ )-breast cancer (BRCA), its efficacy varies between patients. In the present study, Cox multivariate regression of the relative mRNA expression levels in two microarray-based datasets (GSE17005 and GSE26971) was employed to develop a risk score model to evaluate the outcome of patients with BRCA in the GSE17005 dataset. A total of ten genes were used to develop the prediction model for the survival of tamoxifen-treated patients with breast cancer. The survival time of patients in the low risk score group was significantly longer compared with patients in the high risk score group. This observation was validated in three other datasets (GSE26971, GSE22219 and GSE56884). The prognostic effect of the clinicopathological indicators and the risk score were tested with the 5-year event receiving operating characteristic curve, and the risk score had an improved prognostic value in patients with ER+ -BRCA with an area under the curve value of 0.733 compared with the factors of age, tumor stage, tumor grade, chemotherapy, lymph invasion and tumor size. The risk score was significantly associated with the tumor-node-metastasis stage and grade, but was independent of age, sex, lymph invasion and tumor size. In summary, the risk model for breast cancer using the expression signature of ten genes may be an important indicator for predicting the survival of patients with ER+ -breast cancer and treated with tamoxifen.