CHEK2 and melanoma: According to NCCN Guidelines (Version 2.2025, accessed on July 2025), genetic predisposition is defined by the presence of germline mutations or polymorphisms predisposing to melanoma (e.g., CDKN2A, CDK4, MC1R, BAP1 [especially for uveal melanoma], TERT, MITF, and PTEN) and other cancer predisposition genes with increased melanoma risk (e.g., CHEK2, BRCA1/2, BLM, and ATM).