CHEK2 germline loss-of-function alterations have been reported at low frequencies in high-throughput analyses of pediatric cancer cohorts, including neuroblastomas, non-Hodgkin lymphomas, thyroid cancer, melanomas, sarcomas, and brain tumors [2,19,20,21,22,23,24], but the associated clinical phenotypes and outcomes remain poorly described or understood. This evidence concerns the gene CHEK2 and sarcoma.