Breast cancer is a multifactorial disease influenced by genetic, hormonal, environmental, and lifestyle factors. Early diagnosis plays a key role in improving prognosis and increasing patient survival, with imaging, pathological, and immunohistochemical methods serving as the primary tools in this process. In recent years, next-generation sequencing (NGS), and particularly whole exome sequencing (WES), has created a remarkable transformation in identifying the molecular basis of this disease.



WES, by enabling the simultaneous investigation of germline (hereditary) and somatic (acquired) mutations, has played an important role in discovering novel cancer-related genes such as BARD1 and ATRIP. Large-scale studies across diverse populations have confirmed key genes including BRCA1, BRCA2, TP53, PALB2, and CHEK2 as major risk factors. This technology is also applied in determining tumor mutational burden (TMB), investigating intratumoral heterogeneity, and predicting response to immunotherapy.



Despite challenges such as interpreting variants of uncertain significance (VUS), limited racial diversity in studies, and relatively high costs, it is expected that with decreasing costs, standardization of protocols, and integration with emerging technologies such as artificial intelligence and liquid biopsy, the role of WES in accurate diagnosis, molecular classification, and personalized treatment of breast cancer will expand, taking an effective step toward realizing precision medicine.