AlDubayan SH, et al. - In this case-control analysis from January 2016 to May 2018, investigators estimated 205 unselected individuals with testicular germ cell tumors (TGCTs) and 27,173 ancestry-matched cancer-free people from the Exome Aggregation Consortium cohort to assess the improvement of germline pathogenic variants in the Mendelian cancer predisposition DNA repair gene (DRG). They observed that unselected candidates with TGCTs had almost 4 times more germline loss-of-function CHEK2 variants as compared to cancer-free people. They recorded a similar enrichment in 448 unselected Croatian men with TGCTs vs 442 unselected Croatian men without TGCTs (at least 50 years of age) and 231 high-risk cases with TGCTs vs 3090 cases (all older than 50 years) from the Penn Medicine Biobank. Early development of TGCTs was reported in candidates with the pathogenic CHEK2 loss-of-function variants as compared to candidates with CHEK2 wild-type alleles. So, they concluded CHEK2, a novel moderate-penetrance TGCT susceptibility gene.