Immunohistochemistry of normal and hyperplastic ductal breast epithelium

Abstract

Introduction: Immunohistochemistry helps to realize a differential diagnosis of intraductal proliferative lesions of the breast. Biomarkers provide data about the grade of differentiation and size of the lesion, which are necessary to predict the risk of malignancy. Purpose: Immunohistochemical research of normal and hyperplastic ductal breast epithelium and the evaluation of histological subtypes according to the expression of the markers. Material and methods: In the study were included following immunohistochemical markers: CK5/6, CK7/8, 34ᵦE12, p63, E-cadherin, SMA, Ki67, ER, PR, Her2/neu. A rigorous analysis of markers expression has been realized according to DIN (ductal intraepithelial neoplasia) classification, as well has been performed the molecular profile of tumors and differential diagnosis with ductal carcinoma in situ. Results: The ductal and lobular units are consisted of luminal and basal epithelial cells. Luminal cells express CK7/8, CK18/19. The basal compartment contains cells which are immunostained by CK5, CK7, CK14, CK17. UDH (usual ductal hyperplasia) expresses CK5, CK5/6, 34ᵦE12. ADH (atypical ductal hyperplasia) is positive for E-cadherin. In flat epitelial atypia (FEA) the cells are immunostained by CK19, ER, PR. In 75%, DCIS (ductal carcinoma in situ) is positive for ER, PR, Ecadherin. The 34ᵦE12 receptor is expressed in 90% of UDH. The expression of CK5/6 occurs in 96% of ADH and DCIS. The expression of Her2/neu marker reaches 80% in DCIS high grade and has low expression in DCIS low grade. Conclusions: The application of immunohistochemical markers aids the assessment of morphological diagnosis of breast epithelium hyperplasia. Cytokeratins are superior to others in the establishment of cellular source of proliferative lesion and provide an efficient differential diagnosis with malignancies.