Breast Cancer (BC) is a heterogeneous condition that affects a wide range of tumours with various morphological, biochemical, and clinical characteristics. Although there may be phenotypic similarities across tumors, their biological behaviour and therapeutic response frequently differ. With the identification of distinct molecular subclasses, improvements in high-throughput molecular methods and bioinformatics have contributed to a better knowledge of BC biology and to the refining of molecular taxonomy. Although the traditional pathological morphological categorization of BC is crucial and offers diagnostic and prognostic information, the use of single gene and multigene tests to stratify BC into different groups to inform decisions about systemic therapy is now of interest. This study examines methods for categorising BC, along with their drawbacks, and places special focus on the critical significance of morphology in making a precise diagnosis of primary invasive cancer of the breast.
