Expression of Vimentin and Ki-67 in Urothelial Carcinoma of Urinary Bladder: Correlation with Histologic grade and Muscle Invasion

Background: The incidence and prevalence of bladder cancer in developing countries like Bangladesh are rising, with a 5-year prevalence rate of 2.3%. Objective: To observe the expression of Vimentin and Ki-67 in relation to histologic grade and muscle invasion in urothelial carcinoma of the urinary bladder. Method: This prospective, cross-sectional study was conducted from March 2020 to February 2022 at Sir Salimullah Medical College and other institutions in Dhaka. Forty histopathologically confirmed urothelial carcinoma cases were included. Cases with prior radiotherapy/chemotherapy or inadequate specimens were excluded. Vimentin and Ki-67 expression were analyzed in relation to histologic grade and muscle invasion, and statistical significance was assessed using Fisher's Exact Test and Spearman correlation. Results: A total of 40 patients, the mean age was 60.8±9.8 years (range: 37-78); 77.5% presented with hematuria. Male to female ratio was 3.4:1. High-grade tumors (n=27) showed 85.2% Vimentin and 85.2% Ki-67 positivity, significantly higher than low-grade tumors (38.5% Vimentin, 30.8% Ki-67; p=0.008). Muscle-invasive bladder carcinomas (MIBC; n=25) showed 92.0% Vimentin and 84.0% Ki-67 positivity, significantly more than non-muscle-invasive bladder carcinomas (NMIBC; 33.3% Vimentin, 40.0% Ki-67; p<0.001). A weak correlation was observed between Vimentin and Ki-67 expression with MIBCs (rs=0.324, p=0.041). Conclusion: Vimentin and Ki-67 expressions are significantly associated with histologic grade and muscle invasion, indicating their potential prognostic value in urothelial carcinoma of the bladder.