CASR and cancer: It has been well documented that GPCRs can transactivate EGFRs both in ligand-dependent and ligand-independent signaling pathways (Bhola and Grandis, 2008), and the CaSR has been reported to activate the EGFR in this manner in leydig cancer cells, fibroblasts, and prostate cancer cells suggesting that this could be a commonly utilized signaling mechanism (Yano et al., 2004; Tfelt-Hansen et al., 2005; Tomlins et al., 2005).