ERBB2 is a member of the receptor tyrosine kinase family, a subset of receptor proteins that bind epidermal growth factor (EGF). ERBB2 doesn't have a binding domain itself, but stabilizes the configurations of other receptor proteins, making it easier for EGF to latch on. ERBB2 is involved in a lengthy list of important signaling cascades, as EGF is a ubiquitous mitogenic factor that stimulates cell growth in many tissue types. ERBB2's oncogenic effects first came to light in 1987, when it was found to play a major role in breast cancer metastasis. The gene remains primarily associated with breast cancer (20-30% of breast cancer patients have amplified ERBB2) but it's now also considered an important oncogene in uterine, gastric, pancreatic, colorectal and endometrial cancer, among others.