Recent study showed treatment of MCF7 and MDA-MB 468 breast cancer cell lines which have low levels of ErbB2 with anti-ErbB3 antibodies decreased cell migration and proliferation along with decreased PI3K and JNK signaling, raising the possibility that ErbB3 might be target in breast cancer patients whose tumors do not overexpress ErbB228. This evidence concerns the gene ERBB3 and breast cancer.