ATM and breast cancer: To date, most of the ATM mutations observed in breast cancer patients, including the data reported here, are missense mutations distributed throughout the ATM gene, but mainly outside of the PI-3 K domain or other putative functional domains defined by sequence similarity (Savitsky et al. 1995a; Bosotti et al. 2000; Thorstenson et al. 2001; Tavtigian et al. 2009).