Abstract C021: Clinicopathological features and basal-like phenotype expression in triple negative breast cancer at Uyo, Niger-Delta region of Nigeria
Authors: Abudu Emmanuel Kunle , Kanu Obioha , Kudamnya Ikwo Jonathan , Akpanudo Emem Imo , Abudu Oluwasayo Omolara 
Published: December 2023

(A) AN INTRODUCTORY SENTENCE INDICATING THE PURPOSES OF THE STUDY: Patients of African Ancestry (AA) experience higher rates of TNBC and mortality than European Ancestry (EA) patients, despite lower overall breast cancer (BC) incidence. BC is the most frequently diagnosed cancer in Nigeria and USA as well as being the second most common cause of cancer-related death in women, although there have been significant advances in treatment strategies over the past few decades. In addition to conventional therapies, in the molecular era, breast cancer patients often receive targeted treatments based on their unique cancer biology in both adjuvant and neoadjuvant settings. There is limited data on the prevalence of Basal-like breast carcinomas in Nigeria owing to the high cost of gene expression profiling which is the gold standard for molecular classification and immunohistochemistry (which can be used as a surrogate). This study aimed to analyze the clinico-pathological features and immunohistochemical expression of basal-like phenotype in TNBC at Uyo, as well as stratifying of invasive breast carcinomas into main molecular subtypes and correlating the Basal-like breast carcinoma subtype with the size of tumour, grade and age of patient. (B) A BRIEF DESCRIPTION OF PERTINENT EXPERIMENTAL PROCEDURES: One hundred and fifteen formalin fixed, paraffin embedded blocks of Invasive breast carcinomas were assembled, stained and analysed for ER, PR, HER-2, Ki67, CK5/6 and EGFR proteins using immunohistochemistry.  Stratification of invasive breast carcinomas into four (4) main molecular groups (Luminal, HER-2, Basal-like and normal breast subtypes) was done. Patient’s record and immunohistochemical results were reviewed. The data was analyzed and their results were presented as tables, graphs and photomicrographs. (C) A SUMMARY OF THE NEW, UNPUBLISHED DATA: The mean age of the TNBC patients was 39.0 years (range: 25–74 years). Invasive carcinoma (no special type) was the predominant histologic subtype (90.4%). Out of the 115 cases, ER, PR and HER-2 were positive in 53.0 %, 33.0 % and 12.2 % of cases respectively.  CK5/6 and EGFR were also positive in 16.5% and 11.3 % of cases respectively. Ki67 was high (&gt;14 %) in 26.1 % of cases. Our study illustrated that majority of TNBC expressed basal-like markers (51.3 %) and occurred at the 35-44 years age group (33.3%) with a substantial proportion being grade 3 (poorly differentiated) carcinomas (48.7%). There was a significant association between basal-like breast carcinoma and tumour grade.(D) CONCLUSION: Our study illustrated that majority of TNBC expressed basal - like markers and occurred at 35-44 years age group with a substantial proportion being grade 3 (poorly differentiated) carcinomas. There was a positive correlation between basal-like breast carcinoma and tumour grade. It is hoped that research in unraveling  biology of basal-like carcinomas among patients of African Ancestry (AA) and Caucasian Ancestry (CA) will be carried out in the future.

Citation Format: Emmanuel Kunle Abudu, Obioha Kanu, Ikwo Jonathan Kudamnya, Emem Imo Akpanudo, Oluwasayo Omolara Abudu. Clinicopathological features and basal-like phenotype expression in triple negative breast cancer at Uyo, Niger-Delta region of Nigeria [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C021.