BRCA1 and breast cancer: An exploration of a possible difference in histological subtypes of breast cancer in ATM variant carriers compared to other genes implicated in DNA double-strand break repair, such as BRCA1 and BRCA2, was conducted by Abdulrahman et al. in 2018 and showed that tumors of ATM VUS carriers seem smaller, with lower pathologic T stages at diagnosis and greater surrogate molecular subtypes [37].