ERBB2 and breast carcinoma: Of note, the HER-2/EGFRhas been proposed to act as a master regulator of a signaling network thatdrives breast carcinoma epithelial cell proliferation; HER-2 gene amplificationwas observed in 92% of breast cancer specimens and overexpression of HER-2 atthe mRNA, and protein levels have been correlated with cancer virulence, resistance to therapy, and poor prognosis.