Abstract PS19-24: Low expression MicroRNA-195 enriched the cell cycle and cell proliferation gene sets and is associated with advanced grades and worse overall survival of ER positive breast cancer patients

Background: MicroRNA-195 (miR-195) exerts the tumor suppressive functions in various cancers, including breast cancer, by targeting and inhibiting the expressions of the cell cycle and cell proliferation associated genes. In this study, we hypothesized that miR-195 low expressing tumors associate with high proliferative characteristics and poor survival. Material and Methods: We obtained the clinicopathological data and survival information of breast cancer patients from two large publicly available databases; The Cancer Genome Atlas (TCGA) and The Molecular Taxonomy of Breast Cancer International Consortium (METARBRIC). Total of 755 and 1287 patients’ data were obtained from TCGA and METABRIC respectively. Survival analysis, Overall survival (OS) and Disease-free survival (DFS) was performed by comparing the high and low expression groups. CYT score, xCell, and other immunological factors were used to evaluate intratumoral immune cell composition. Also, gene set enrichment analysis (GSEA) was performed between miR-195 high and low expression groups. Results: The patients were divided into miR-195 high and low groups by utilizing median cutoff. Advanced grades were significantly associated with lower expression of miR-195 in ER positive/HER2 negative (ER+/HER2) subtype with both TCGA and METABRIC cohorts (p Citation Format: Yoshihisa Tokumaru, Masanori Oshi, Eriko Katsuta, Nobuhisa Matsuhashi, Manabu Futamura, Kazuhiro Yoshida, Kazuaki Takabe. Low expression MicroRNA-195 enriched the cell cycle and cell proliferation gene sets and is associated with advanced grades and worse overall survival of ER positive breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS19-24.