KIT and testicular germ cell tumor: Several genes have been associated to the development of TGCT (Rapley and Nathanson, 2010; Landero-Huerta et al., 2017), but only a few of them, such as KIT gene expression (Vigueras-Villaseñor et al., 2015), or polyQ inserts in exon 1 of the AR gene (Ferlin et al., 2005; Davis-Dao et al., 2011; Hutson et al., 2015; Fukawa and Kanayama, 2018) have been analyzed in patients with CO, without establish a relationship between CO and TGCT.