ERBB2 and breast carcinoma: In addition, a low ratio of miR-125a/b: HER2mRNAs and high ratios of miR-125a/b: HER3 mRNA and HER2:HER3 mRNAs were displayed in HER2 gene-amplified and protein-overexpressing breast cancer cells (Fig. 5a), which further indicates that the interaction between HER2 and HER3 mRNA may occur under such a circumstance.