ERBB2 and breast cancer: The cytotoxic effect of the combined treatment in breast cancer cells was validated by the MTT assay in the TNBC cell lines (Additional file 1: Fig. S1c) and was further extended to the MCF7 (luminal type A) and SKBR-3 (HER2 positive) breast cancer cell lines, representing clinically and pathologically distinct forms of breast carcinoma (Additional file 1: Fig. S1b).