In our panel of cancer cell lines, there were four breast cancer cell lines (ZR-75-1, SKBR3, MDA-MB-231, and MCF7) among which only two cell lines were considered to overexpress ErbB2, SKBR3, which is scored at 3+, and ZR-75-1, which is scored at 2+. This evidence concerns the gene ERBB2 and breast cancer.