GPC1 and testicular germ cell tumor: Cancers with the most significant decreased expression of GPC-1 were found in Skin Cutaneous Melanoma (SKCM, P = 7.36e−114), followed by Testicular Germ Cell Tumors (TCGT, P = 1.46e−51) and Prostate adenocarcinoma (PRAD, P = 4.32e−43).