Pattern of Molecular Phenotypes of Breast Carcinomas using Immunohistochemistry in a District Hospital in Nigeria

Abstract

Background: Cancer of the breast is the most common organ-specific cancer, affecting women worldwide with disproportionately higher mortality seen among women of Africa ancestry. Molecular phenotyping is crucial for tailored treatment of such patients. Aim: The aim of the study is to describe the molecular phenotypes of carcinomas of the breast based on their oestrogen, progesterone, and HER-2/Neu receptors status in our centre. Design: This was a retrospective analysis of 136 histologically diagnosed breast carcinomas, for which oestrogen, progesterone, and HER2 receptors status data were available at the Pathology Unit in a Nigerian District Hospital. Materials and Methods: Relevant biodata and pathology and molecular information of all patients with histologically diagnosed breast cancer (BC) were extracted from patients' forms and reports archived in the department. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue blocks of 136 (54.4%) cases of the BCs utilizing the avidin-biotin complex technique. Results: The ages of the patients ranged from 17 to 74 years, and the mean age was 47.3 ± 11.7 at diagnosis. All affected patients were females except for a male teenager. oestrogen, progesterone, and HER-2/Neu receptor-positive breast carcinomas were 43.4% (59), 39% (53), and 27.2% (37), respectively. Triple-negative breast carcinoma (39%, 53/136) was the most prevalent phenotype, followed by Luminal A (33.8%, 46/136) and Luminal B (14.7%, 20/136), while HER2-enriched (12.5%, 17/136) was the least common molecular subtype in our series. Conclusion: Breast carcinomas are predominantly of the triple-negative molecular phenotype in our setting and commonly affected young women.