Prognostic value of a BCSC-associated microRNA signature in hormone receptor-positive HER2-negative breast cancer.

532Background: Breast cancer patients with high proportion of cancer stem cells (BCSCs) are more chemotherapy-resistant and have unfavorable clinical outcomes. MicroRNAs (miRNAs) can function as oncogenes or tumor suppressor genes, which regulate key features of BCSCs. Since BCSCs have unique miRNA expression profile, we hypothesized that a biology-driven model based on BCSC-associated miRNAs could provide prognostic information for low recurrent-risk HR+HER2- breast cancer patients. Methods: A systematic literature reviewing suggested 50 BCSC-associated miRNAs that regulate the BCSC features. We excluded 15 of these miRNAs as they were not constantly detectable in the 40 paraffin embedded tumor samples by qRT-PCR (A pilot assay). A total of 35 BCSC-associated miRNAs were identified. We randomly assigned 303 patients into a training group (n = 202) and an internal validation (n = 101) group. We built a 10-miRNA-based classifier using a LASSO Cox model in the training group and validated its prognostic in ...