Uridine 5'diphospho-glucuronosyltransferase 1A expression as an independent prognosticator in urothelial carcinoma of the upper urinary tract

Objective: To determine the expression status of uridine 5'diphospho-glucuronosyltransferase 1A, a major phase II drug metabolism enzyme, in upper urinary tract urothelial carcinoma, as well as to assess its prognostic significance.

Methods: We immunohistochemically stained for uridine 5'diphospho-glucuronosyltransferase 1A in tissue microarray consisting of 99 upper urinary tract urothelial carcinoma samples and paired non-neoplastic urothelial tissues. We also assessed the effect of uridine 5'diphospho-glucuronosyltransferase 1A knockdown on urothelial cancer cell growth.

Results: Uridine 5'diphospho-glucuronosyltransferase 1A was positive in 92.9% (27.3% weak [1+], 37.4% moderate [2+], 28.3% strong [3+]) of tumors, which was significantly (P < 0.001) lower than in benign urothelial tissues (98.8%; 3.5% 1+, 18.8% 2+, 76.4% 3+). All 37 (100%) non-muscle-invasive versus 55 (88.7%) of 62 muscle-invasive tumors (P = 0.043) were immunoreactive for uridine 5'diphospho-glucuronosyltransferase 1A. The rates of moderate-to-strong uridine 5'diphospho-glucuronosyltransferase 1A expression and its positivity were also strongly associated with the absence of concomitant carcinoma in situ (P = 0.034) and lymphovascular invasion (P = 0.016), respectively. However, there were no statistically significant associations between uridine 5'diphospho-glucuronosyltransferase 1A expression and tumor grade or pN/M status. Uridine 5'diphospho-glucuronosyltransferase 1A loss in M0 tumors was strongly associated with lower progression-free survival (P < 0.001) and cancer-specific survival (P < 0.001) rates. Multivariate analysis further identified a strong correlation of uridine 5'diphospho-glucuronosyltransferase 1A positivity with reduced cancer-specific mortality (hazard ratio 0.28, P = 0.018). Meanwhile, uridine 5'diphospho-glucuronosyltransferase 1A knockdown in urothelial cancer cells resulted in significant increases in their viability and migration.

Conclusions: These results suggest a preventive role of uridine 5'diphospho-glucuronosyltransferase 1A signals in the development and progression of upper urinary tract urothelial carcinoma. Loss of uridine 5'diphospho-glucuronosyltransferase 1A expression might serve as an independent predictor of poor prognosis in patients with upper urinary tract urothelial carcinoma.