Prevalence of basal-like phenotype in triple-negative invasive breast carcinomas and a review of the literature

Abstract

Objectives: The study is aimed at analyzing the clinico-pathological features and immunohistochemical expression of basal-like phenotype in triple-negative breast carcinomas (TNBC) as well as stratifying of invasive breast carcinomas into main molecular subtypes and correlating the Basal-like breast carcinoma subtype with the size of tumor, grade and age of patient in the University of Uyo Teaching Hospital, Uyo, Akwa Ibom State, Nigeria. Material and Methods: This study was a descriptive cross-sectional hospital-based, that was carried out in the Histopathology Department of the University of Uyo Teaching Hospital, Uyo, Akwa Ibom State, Nigeria, using paraffin-embedded tissue blocks of invasive carcinomas of breast received between July 01, 2016, and August 31, 2018, subject to re-histological assessment and IHC staining for various breast carcinoma markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal receptor-2 (HER-2), Ki67, epidermal growth factor receptor (EGFR), and CK5/6. The age of patients and tumor size was accessed from the records of the department. The data were analyzed by descriptive and inferential statistics using the Statistical Package for the Social Sciences version 16. Results: A total of 79 histologically confirmed invasive breast carcinomas in females were analyzed. The age range of the patients was 24–76 years, with a mean age of 43.96 ± 9 years. The majority of the invasive carcinomas were of no special type (91.1%). ER, PR, and HER-2 were positive in 53.2%, 32.9%, and 12.7% of cases, respectively. Phenotypic classification based on immunohistochemistry showed that the Luminal A subtype was the predominant subtype, accounting for 45.3% of cases, while Luminal B, HER-2 enriched, basal-like, and unclassified were 13.3%, 5.3%, 17.3%, and 18.7%, respectively. Triple-negative breast carcinomas (TNBCs) accounted for 36.0% of the cases. The frequency of basal-like breast carcinoma in TNBCs was 48.1%. Conclusion: Our study confirmed that the Luminal A subtype of breast carcinomas was the commonest, and there was an appreciable number of the basal-like breast carcinoma subtype in Uyo, with a frequency of 48.1% among the TNBCs.