Expression patterns of EGFR, PD-L1, and Ki-67 among Ugandan patients with muscle-invasive bladder cancer

Abstract

Introduction: Bladder cancer ranks as the ninth most common cancer globally, with muscle-invasive urothelial carcinoma (MIUC) exhibiting poor survival rates. Biomarkers such as epidermal growth factor receptor (EGFR), programmed death-ligand 1 (PD-L1), and Ki-67 have been studied for their potential in guiding management. However, limited data exists on their expression in Ugandan populations. This study examines the expression of these biomarkers in MIUC patients to provide insights for improved management.

Methods: A descriptive, cross-sectional study was conducted on 52 archived formalin-fixed, paraffin-embedded (FFPE) tissue samples of MIUC patients at Mulago National Referral Hospital (MNRH). Immunohistochemistry (IHC) was performed using the Ventana BenchMark ULTRA system with antibodies against PD-L1, EGFR, and Ki-67. Expression thresholds were set at > 5% for PD-L1, > 10% for EGFR, and > 15% for Ki-67. Data were analysed using RStudio, with associations assessed using Cramér’s V matrix.

Results: Among the 52 samples, Ki-67 showed the highest expression (55.8%), followed by EGFR (13.5%) and PD-L1 (5.8%). Most associations between categorical variables were weak, with a moderate association demonstrated between variant histology and lymphovascular invasion (LVI).

Conclusion: This study highlights the low expression of PD-L1 and EGFR in contrast to the high expression of Ki-67. These findings emphasise the importance of considering Ki-67 as a potential biomarker for aggressiveness in urothelial carcinoma (UC). The low PD-L1 expression raises questions about the applicability of immunotherapy in Ugandan populations. Future research with larger cohorts and genomic analysis is recommended.