Prevalence of Molecular Subtypes of Breast Carcinoma in University of Calabar Teaching Hospital using Immunohistochemistry as surrogates for Intrinsic DNA gene characteristics

Background:Breast cancer is a heterogeneous disease that shows inter and intra-lesion variation. The classification into molecular subtypes has made chemotherapeutic management of breast cancer easier and patient-specific with excellent outcomes. Immunohistochemistry are used as surrogates for intrinsic DNA gene in most resource poor countries. Aimsand objectives: This study aimed to describe prevalence of molecular subtypes of breast carcinoma using immunohistochemistry as surrogates for characteristics seen with intrinsic DNA gene. Methodology:The immunohistochemistry for oestrogen receptor, (ER), progesterone receptor (PR) and Human epidermal receptor2 (HER2) of the breast carcinoma diagnosed in the university of Calabar Teaching Hospital in a five year period from 1 st January 2010 to 31 December 2014 were collated. An algorithm is developed to determine the molecular subtypes. Luminal A (ER+/PR-, ER-/PR+. HER2-), Luminal B (ER+/PR-, ER-/PR+ and HER2+), Basal-like (ER-, PR-,HER2-) and Her 2 Type (HER2+, ER-, PR-)). The prevalence of each subtype is determined and each tumour characteristics in terms of age of subject, tumour size, histologic grade and histologic type is described. The findings are presented in charts and tables and statistical significance determined. Results: Luminal A is (52.38%), Triple negative (26.53%), Luminal B (12.93%) and Her2 positive (8.16%). The Luminal molecular subtype accounted for 65.31%. All the males had Luminal A subtype. Conclusion: The most common molecular subtype is Luminal A.