TP53 and breast cancer: Recent studies have shown that miR-31 expression is specifically attenuated in metastatic breast cancer cell lines and miR-31 inhibits breast cancer metastasis by targeting multiple genes [17]; miR-31 is underexpressed in serous ovarian carcinomas, and in a number of serous cancer cell lines with a dysfunctional p53 pathway (OVCAR8, OVCA433, and SKOV3), miR-31 overexpression inhibits proliferation and induces apoptosis; however, in other lines with functional p53 (HEY and OVSAYO), miR-31 has no effect [18].