Exploring the Role Of CD155 in Urothelial Carcinoma of the Urinary Bladder: An Immunohistochemical Study & Its Correlation With PD-L1

BACKGROUND: Urinary bladder carcinoma is one of the most immunogenic cancers. Several immune checkpoint inhibitors targeting programmed death-ligand 1 (PD-L1) have been approved by the FDA for bladder carcinoma treatment. However, additional immunotherapeutic targets are still needed. CD155 is another immune checkpoint molecule that has been shown to be overexpressed in several cancers and is associated with poor prognosis. AIM: This study aimed to evaluate CD155 expression in cases of urinary bladder urothelial carcinoma using immunohistochemistry and to correlate this expression with the clinicopathological parameters of the cases as well as with PD-L1 expression. METHODS: Immunohistochemical staining for CD155 and PD-L1 was performed on 67 cases of urothelial carcinoma of the urinary bladder. RESULTS: CD155 was positive in 41.8% of cases and was significantly associated with invasive tumors and advanced T stage. PD-L1 was positive in 35.8% of cases and was significantly associated with advanced T stage, distant metastasis, muscle invasion and lymphovascular emboli. A statistically significant positive correlation was observed between the expression of both CD155 and PD-L1. CONCLUSION: Our study demonstrated increased expression of CD155 in urothelial carcinoma of the urinary bladder with advancing stage, suggesting its potential as a therapeutic target. Additionally, CD155 expression correlated positively with PD-L1 expression, indicating that some patients might benefit from a combined blockade of both targets.