CHEK1 and neoplasm: In nearly all (13/14) EP tumours, deleterious alterations were identified in multiple HRR components, including PTEN (phosphatase and tensin homologue); BARD1 (BRCA1 associated RING domain 1); ATM (ataxia telangiectasia mutated); BRCA1 (breast cancer type 1 susceptibility protein); BRCA2 (breast cancer type 2 susceptibility protein); CHEK1 (checkpoint kinase 1); and ATR (ataxia telangiectasia and Rad3-related protein).