Classification of breast cancers

Abstract

Breast cancer is a complex and heterogeneous disease, demanding a nuanced classification system to inform diagnosis, prognosis, and therapeutic decisions. This chapter provides a thorough exploration of breast cancer classifications that includes histopathological, molecular, and immunohistochemical approaches. Histopathological classification lays the foundation for dissecting breast cancer into distinct types based on cellular morphology and architectural features. Ductal and lobular carcinomas, sarcomas, and lymphomas are among the recognized subtypes, each offering unique insights into tumor behavior. Immunohistochemical classification introduces the critical role of biomarkers. Estrogen and progesterone receptors, HER2/neu, and the Ki- 67 proliferation index are crucial in identifying treatment options and stratifying patients. Triple-negative breast cancer (TNBC), characterized by the absence of these markers, challenges clinicians and researchers alike, demanding innovative approaches. Molecular classification delves deeper, scrutinizing the genetic underpinnings of breast cancer. Notably, the PAM50 intrinsic subtypes, Luminal A, Luminal B, HER2-enriched, and Basal-like, guide personalized treatment strategies and prognosis prediction, offering a molecular lens into this heterogeneous disease. This chapter synthesizes the intricacies of these classifications, highlighting their clinical significance, evolving landscape, and impact on customized therapeutic interventions. As we unravel the intricate tapestry of breast cancer, these classifications stand as beacons, guiding our understanding and ultimately improving patient care.