Molecular subtypes of breast carcinoma in Egyptian women: clinicopathological features

Breast carcinoma may be classified into distinct molecular subtypes based on immunohistochemical markers for estrogen, progesterone and Her-2/neu receptors. The aim of the study was to identify the clinicopathological features of the molecular subtypes of breast carcinoma in our locality. A total of 274 surgically resected breast carcinomas were selected from the files of the Dr. KRZ referral pathology laboratory, Mansoura, Egypt, and the Pathology Department of Mansoura University. Molecular subtypes were classified into luminal A, luminal B, Her-2/neu-expressing and triple-negative. Clinicopathological and histological features of molecular subtypes were analyzed. Luminal A subtype was the most prevalent (41.2%), followed by triple-negative subtype (28.5%), then Her2-expressing subtype (19.4%) and luminal B subtype (13.9%). The commonest histological type was infiltrating duct carcinoma (83.2%), followed by infiltrating lobular carcinoma (9.1%) and medullary carcinoma (3.2%). The luminal A subtype was significantly correlated to low tumor grade, lower number of positive lymph nodes metastasis, absence of both necrosis and syncytial growth pattern. We concluded that the commonest molecular subtype of invasive breast carcinoma among Egyptian women is luminal subtype A, which displayed favorable features. Triple-negative subtype and medullary carcinomas are present in a ratio higher than in western countries.