Specific cell differentiation in breast cancer: a basis for histological classification.

Publisher: BMJ Pub. Group Country of Publication: England NLM ID: 0376601 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1472-4146 (Electronic) Linking ISSN: 00219746 NLM ISO Abbreviation: J Clin Pathol Subsets: MEDLINE

Publication: London : BMJ Pub. Group
Original Publication: London : British Medical Association

Cell Differentiation*; Breast Neoplasms/*pathology ; Carcinoma/*pathology ; Neoplastic Stem Cells/*pathology ; Neuroendocrine Tumors/*pathology; Biomarkers, Tumor/genetics ; Biomarkers, Tumor/metabolism ; Breast Neoplasms/classification ; Breast Neoplasms/genetics ; Breast Neoplasms/metabolism ; Carcinoma/classification ; Carcinoma/genetics ; Carcinoma/metabolism ; Cell Lineage ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Metaplasia ; Neoplasm Grading ; Neoplastic Stem Cells/metabolism ; Neuroendocrine Tumors/classification ; Neuroendocrine Tumors/genetics ; Neuroendocrine Tumors/metabolism ; Phenotype

Breast parenchyma progenitor cells show a high degree of phenotypic plasticity reflected in the wide range of morphology observed in benign and malignant breast tumours. Although there is evidence suggesting that all breast cancer (BC) arises from a common epithelial progenitor or stem cell located at the terminal duct lobular units (TDLUs), BC shows a broad spectrum of morphology with extensive variation in histological type and grade. This is related to the complexity of BC carcinogenesis including initial genetic changes in the cell of origin, subsequent genetic and epigenetic alterations and reprogramming that occur at various stages of BC development and the interplay with the surrounding microenvironment, factors which influence the process of differentiation. Differentiation in BC determines the morphology, which can be measured using histological grade and tumour type. Histological grade, which measures the similarity to the TDLUs, reflects the degree of differentiation whereas tumour type reflects the type of differentiation. Understanding BC phenotypic differentiation facilitates the accurate diagnosis and histological classification of BC with corresponding clinical implications in terms of disease behaviour, prognosis and management plans. In this review, we highlight the potential pathways that BC stem cells follow resulting in the development of different histological types of BC and how knowledge of these pathways impacts our ability to classify BC in diagnostic practice. We also discuss the role of cellular differentiation in producing metaplastic and neuroendocrine carcinomas of the breast and how the latter differ from their counterparts in other organs, with emphasis on clinical relevance.
Competing Interests: Competing interests: None declared.
(© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Keywords: breast neoplasms; cell differentiation; morphological and microscopic findings

0 (Biomarkers, Tumor)

Date Created: 20210729 Date Completed: 20220131 Latest Revision: 20220131

20240105

10.1136/jclinpath-2021-207487

34321225