[Pathological examination in breast oncology: Overview of histological types, examination procedures, predictive and...

Histopathological examination is a cornerstone in the diagnosis, prognostic stratification, and therapeutic planning of breast cancer. It combines morphological, immunophenotypic, and molecular data to guide clinical decision-making. This article provides a comprehensive overview of the main histological types, technical modalities, and conventional and emerging biomarkers in breast cancer pathology. Breast carcinomas are categorized into in situ (DCIS, LCIS) and invasive forms. The most frequent invasive types are invasive carcinoma of no special type (NST) and invasive lobular carcinoma (ILC). Rare histologic variants (e.g., mucinous, micropapillary, metaplastic) exhibit distinct biological and prognostic features. The diagnostic workflow includes standardized steps: sampling, formalin fixation, paraffin embedding, H&E staining, immunohistochemistry (ER, PR, HER2, Ki-67), and molecular testing when needed (FISH, PCR, NGS). Routine biomarkers help define surrogate molecular subtypes (luminal A/B, HER2-positive, triple-negative) and guide systemic therapies. The emergence of the HER2-low category exemplifies how biomarker refinement impacts clinical practice. Additional markers such as PIK3CA and ESR1 mutations, BRCA/HRD status, PD-L1 expression, and tumor-infiltrating lymphocytes (TILs), along with multigene signatures (e.g., Oncotype DX, MammaPrint), further individualize prognostic assessment and treatment selection. Innovative approaches such as liquid biopsy and next-generation sequencing (NGS) enable minimally invasive monitoring and personalized care, especially in advanced disease. Breast cancer pathology is thus a dynamic, integrative discipline central to precision oncology, driven by ongoing technological and molecular advances, and essential to multidisciplinary cancer care.