ERBB2 and cancer: To assess the effect of the HER2 G776S mutation on the HER2 downstream signaling pathway in human cancer cells, we transfected HER2 WT or HER2 G776S expression vectors into several human cell lines: HeLa (cervical cancer cells), FHC (fetal human colon epithelial cells), CACO-2 (colorectal cancer cells) and COLO-320 cells (colorectal cancer cells).