CHEK1 and neoplasm: For PROPEL, both tumor tissue (FoundationOne CDX) and ctDNA-based (FoundationOne Liquid CDx) tests were employed to detect pathogenic variants in the assessed genes (ATM, BRCA1, BRCA2, BARD1, BRIP1, CDK12, CHEK1, CHEK2, FANCL, PALB2, RAD51B, RAD51C, RAD51D, and RAD54L) and a post hoc analysis combining tumor tissue and ctDNA data was carried out to increase the number of patients with a deficit in HRR and to at least reduce false negatives [87].