SPAG6 and cancer: Sperm-associated antigen 6 (SPAG6) gene, first identified in human testicular tissue, also named CT141 and pf16, is considered a cancer-testis antigen (CTA) and involved in many cancers (Abe et al., 2008; Silina et al., 2011; Coan et al., 2018; Jiang et al., 2019).