SELENOW and breast cancer: These results indicated that suppression of malignant phenotypes of breast cancer cells by piR-36,712 may be mediated by SEPW1P and SEPW1. Indeed, overexpression of SEPW1P or SEPW1 could reverse the inhibitory effect of piR-36,712 on proliferation of MCF7 and ZR75–1 cells (Fig. 5c) and silencing SEPW1P or SEPW1 expression abolished the enhancement of MCF7 and ZR75–1 proliferation caused by knockdown of piR-36,712 (Fig. 5d).