Immunohistochemical profiling of HER-2/neu, steroid hormone receptors and KI-67 biomarkers in a cohort of Nigerian women with breast cancer

Background: Progressive improvement in the accuracy of profiling of hormone receptors in breast cancer provides the basis for targeted endocrine therapy, a major pillar of multimodal breast cancer treatment. However, the disparity in findings from comparatively smaller sample-sized studies in West Africa has led to somewhat conflicting conclusions and recommendations. Objectives: This study investigates the immunohistochemical (IHC) profile of breast cancer specimens for estrogen receptor (ER), progesterone receptor (PR), human epidermal receptor-2 (HER2)/neu, and Ki-67 in a tertiary hospital in Ibadan, Nigeria over 12 years. Materials and Methods: We reviewed 998 IHC reports, documented clinicopathologic parameters, computed patterns of biomarkers, and stratified them based on the American Society of Clinical Oncology/College of American Pathologists recommendations. Descriptive analysis including frequency, mean, and median were generated from the data extracted. Results: Out of the 998 cases, 975 (97.7%) were females and 23 (2.3%) were males. The mean age was 48.84 ± 11.99 years. Open biopsies were the most common types of specimens (320, 41.6%): lumpectomy and incisional biopsy of ulcerated, fungating or unresectable tumours. In those cases, 246 (32.0%) were samples of breast-conserving or ablative surgical extirpation (mastectomy/wide local excision/quadrantectomy), and 203 (26.4%) were obtained by core needle biopsies. Invasive ductal carcinoma was the most common histopathological type (673, 94.5%). The majority of graded tumours were intermediate grade (444, 53.5%). Four hundred and sixty-nine (48.4%) were ER positive, 414 (42.8%) were PR positive, and 180 (19.4%) were HER2/neu positive. Three hundred and thirty-four (34.0%) were triple-negative. Eighty-nine cases had Ki-67 staining done, and of these 61 (68.5%) had positive nuclear staining. Conclusion: Steroid hormone receptors and HER-2/neu proportions in our cohort are likely to be more representative than the widely varied figures hitherto reported in the sub-region. We advocate routine IHC analysis of breast cancer samples as a guide to personalized endocrine therapy.