Tyrosine kinase signalling in breast cancer - Epidermal growth factor receptor and c-Src interactions in breast cancer

Both the non-receptor tyrosine kinase, c-Src, and members of the epidermal growth factor (EGF) receptor family are overexpressed in high percentages o f human breast cancers. Because these molecules are plasma membrane-associa ted and involved in mitogenesis, it has been speculated that they function in concert with one another to promote breast cancer development and progre ssion. Evidence to date supports a model wherein c-Src potentiates the surv ival, proliferation and tumorigenesis of EGF receptor family members, in pa rt by associating with them. Phosphorylation of the EGF receptor by c-SRC i s also critical for mitogenic signaling initiated by the EGF receptor itsel f, as well as by several G-protein coupled receptors (GPCRs), a cytokine re ceptor, and the estrogen receptor. Thus, c-Src appears to have pleiotropic effects on cancer cells by modulating the action of multiple growth-promoti ng receptors.