CHEK2 and breast carcinoma: Specifically, ATM c.7271C>G has been associated with a more substantial breast cancer risk in several studies.7, 13 Le Calvez-Kelm et al,11 estimated that the ORs associated with rare mutations in CHEK2 from similarly designed studies were 6.18 (95% CI 1.76 to 21.8) for rare protein-truncating and splice-junction variants and 8.75 (95% CI 1.06 to 72.2) for evolutionarily unlikely missense substitutions.11