Regardless the levels of peptides receptors on prostate cancer (affected or not by tumor progression) [49], postreceptor signaling defects, such as loss of SHP-1, may play a role in the pathogenesis of prostate cancer by short-circuiting in signaling pathways of these antiproliferative peptides with persistence of signals generated by growth factors. The gene discussed is PTPN6; the disease is prostate cancer.