BRCA1 and breast cancer: The expression of PTEN and BRCA1 in ZR75-1 and HCC1419 breast cancer cells and malignant breast cancer tissues (Fig. S4, S7 and S8), however, was not negatively correlated with the miR-20b expression (Fig. 2A and 6B), implicating the involvement of other factors/mechanisms in the expression of PTEN and BRCA1, in addition to miR-20b.