EGFR and cancer: In the former system, G-protein-mediated production of AMP promotes PKA activation, PKA up-regulates Src (as seen in capacitated sperm), Src activates the secretion of heparin-binding EGF-like growth factor via MMP activation, thereby activating EGFR/kinase, and Src also affects the activity of EGFR/kinase through direct phosphorylation on tyrosine 845 [178], an Src-dependent phosphorylation site, whose phosphorylation has been implicated in some types of cancer cells [180–182].