We first analyzed using qRT-PCR the expression of miR-125a-5p in a cohort of breast cancer cell lines including MDA-MB-435, MDA-MB-231, MCF-7, its HER2/ErbB2-overexpressing derivative MCF-7/Her18, R2d, and R2N1d (Figure 2, A). This evidence concerns the gene ERBB2 and breast carcinoma.