In addition, profiling studies have implicated a number of receptor tyrosine kinases as being overexpressed in differing stages of prostate cancer, including the erbB kinase family (ErbB1 (epidermal growth factor receptor, (EGFR)), ErbB2 (HER2/neu), and ErbB3 (HER3)), the insulin-like growth factor receptor (IGF-1R), and the platelet-derived growth factor receptor (PDGF-R). This evidence concerns the gene EGFR and prostate cancer.