Expression of Indoleamine 2,3-Dioxygenase Gene Is a Feature of Poorly Differentiated Non-muscle-invasive Urothelial Cell Bladder Carcinomas.

Aim: To evaluate indoleamine 2,3-dioxygenase (IDO) gene expression in non-muscle-invasive urothelial cell bladder carcinoma (NMIBC).

Patients And Methods: Seventy-four patients undergoing surgical treatment for NMIBC were enrolled in the study. IDO gene expression was assessed by quantitative real-time polymerase chain reaction (qRT-PCR).

Results: IDO gene expression was detectable significantly more frequently (48/74, 64.86% vs. 5/21, 23.81%, p<0.001) and to significantly higher extents (p=0.01) in cancer tissues than in normal bladder mucosa. IDO gene expression was observed significantly more frequently in large (p=0.02), high-grade (p=0.05) and stage T1 (p=0.03) than in small, low-grade and stage Ta tumors. Expression levels were also significantly higher in large, high-grade and stage T1 tumors (p<0.01, p=0.05 and p=0.03, respectively). A direct positive correlation between IDO gene expression in tumor tissues and tumor size (R=0.24, p=0.04), grade (R=0.23, p=0.05) and stage (R=0.25, p=0.03) was detected. Multivariate analysis suggested a trend (p=0.08) towards longer overall survival in patients bearing tumors that did not express IDO gene.

Conclusion: These data indicate that IDO gene expression is a feature of aggressive NMIBC, suggesting a potential immunosuppressive role of IDO.