HLA-B expression in breast cancer patients in southwestern Nigeria: A descriptive study

Introduction: This study aimed to evaluate human leukocyte antigen B (HLA-B) expression in breast cancer tissues from two tertiary health institutions in southwestern Nigeria and explore its relationship with age at diagnosis. Methods: A cross-sectional study was conducted to investigate the immunohistochemical expression of HLA-B in the histologic tissues of breast cancer patients at the Obafemi Awolowo University Teaching Hospitals Complex, which was diagnosed between January 1, 2022, and December 31, 2022. The tissue samples were formalin fixed and paraffin embedded (FFPE) to preserve their morphology and antigenicity. We used an anti-HLA-B antibody (Clone PAS-35345) from Thermo Fisher Scientific as the primary antibody. Results: Thirty-eight cases of breast cancer were evaluated during the study period. Half of the breast cancer patients expressed little or no HLA-B protein. High and moderate expression was observed in only 7 (18.4%) and 10 (26.3%) of the patients, respectively. A comparison of the expression of HLA-B across the different age groups revealed no statistically significant differences between the age groups (p = 0.898). Conclusion: Our study revealed that over 40% of breast cancer patients exhibited moderate to high HLA-B expression, suggesting that a significant proportion of these cancers may be amenable to immunotherapy. There was no significant variation in the degree of expression of HLA-B across the various age groups at presentation. This could also mean that HLA-B expression is not particularly related to early-onset breast cancer.