CDKN1B and breast cancer: Indeed, our data showed that co-expression of miR-125a and miR-205 was more potent than either miRNA alone to inhibit erbB3 expression, decrease the levels of p-HER3, p-Src, p-Akt, and E2F1, and induce expression of p27kip1 in HER2-overexpressing breast cancer cells.