NTRK1 and testicular germ cell tumor: Results from a genome-wide scan among 277 cases of testicular germ cell tumors (TGCT) and a subsequent replication study on 371 cases were reported by Kanetsky et al. in 2009 [142] whereby genetic variation of KITLG (gene encoding the ligand for the receptor tyrosine kinase c-KIT) and Spry4 was shown to predispose to testicular germ cell cancer.