Breast cancer subtypes in CHEK2, ATM, and other non-BRCA germline carriers in Turkey

Introduction: Breast cancer (BC) is a heterogeneous disease with a hereditary component, but the impact of non-BRCA germline variants on tumor subtypes remains underexplored, particularly in diverse populations. This study aims to describe the distribution of immunohistochemical (IHC) subtypes in a Turkish BC patient cohort with pathogenic or likely pathogenic variants (PVs/LPVs) in non-BRCA susceptibility genes.