Both RTKs (such as FGFR, EGFR, PDGFR, and VEGFR) and NRTKs (such as SRC) are very important in the carcinogenesis and progression of PCa, and are potential targets for the treatment of PCa.497,498 Signal transductions through ligands binding with RTKs or stimulation of unique NRTKs lead to cross-phosphorylation of specific tyrosine residues, which activate downstream signaling such as PI3K/AKT, phospholipase C, and Janus tyrosine kinase.499,500 The signaling subsequently regulates the transcription of genes involved in proliferation, survival and differentiation.499. This evidence concerns the gene EGFR and posterior cortical atrophy.