ESR1 and breast neoplasm: For example, pathogenic variants in BRCA1 often lead to triple-negative (estrogen [ER], progesterone [PR], and human epidermal growth factor 2 [HER2] receptor negative) breast tumors that commonly overlap with basal-like type [18, 19], whereas ATM and CHEK2 variants associate with ER-positive tumors [20, 21].