Taken together, our findings and those by Massink et al. (20) indicate that CHEK2-associated BCs are phenotypically and genomically distinct from BRCA1- and BRCA2-associated BCs, but similar to ATM-associated BCs in that these tumors are preferentially ER positive, lack genomic features suggestive of HRD, and rarely harbor TP53 mutations. The gene discussed is CHEK2; the disease is hypoparathyroidism-retardation-dysmorphism syndrome.