ATM and cancer: The RS patients’ whose cells were studied here were from phenotypically normal individuals with unexpected severe RT reactions in their normal tissues; no cases had the stigmata of the known RS syndromes, involving genes such as ATM, NBS and BRCA. A subset of the RS cases and controls had previously been screened for mutations in the BRCA1 and BRCA2 cancer predisposition/radiation response genes, with no definite mutations being found (Leong et al, 2000).