Association between PSCA mRNA expression levels and rs2294008 polymorphism in transitional cell cancer of the bladder.

Prostate stem cell antigen (PSCA) was originally identified as a gene that is overexpressed in prostate cancer, and correlates with prostate cancer progression and prognosis. Recently, a significant association has been identified between the PSCA rs2294008 (C>T) polymorphism and the risk of developing bladder cancer. Therefore, the present study investigated the different expression levels of PSCA mRNA in transitional cell carcinoma (TCC) of the bladder and normal bladder tissue. Furthermore, the association between PSCA mRNA expression levels in TCC and different rs2294008 (C>T) genotypes and various clinicopathological features, including tumor stage and grade, were evaluated. Reverse transcription-quantitative polymerase chain reaction was performed on 80 TCC samples and 38 samples of normal bladder urothelium from TCC patients who underwent transurethral resection of bladder tumor or radical cystectomy at the Beijing Friendship Hospital (Beijing, China) between September 2010 and May 2011. Genomic DNA was extracted from tumor tissue and sequenced to determine the rs2294008 (C>T) genotype. PSCA mRNA expression was detected in all samples (100%); however, tumor samples exhibited significantly higher PSCA expression levels compared with the normal urothelium samples (P=0.038). PSCA mRNA expression was positively correlated with the histological grade of the tumor (G1-2 vs. G3; P=0.001); however, no significant difference was detected between patients with superficial (Ta or T1) and muscle-invasive (≥pT2) tumors (P=0.250). Thus, PSCA mRNA expression levels were associated with TCC and tumor histological grade, but not the tumor stage. Additionally, PSCA mRNA expression levels were significantly higher in T allele carriers compared with CC homozygous patients (P=0.001), indicating that the presence of the T allele may increase PSCA mRNA expression. Therefore, rs2294008 (C>T) may be associated with the biological properties of TCC and, thus, future research should focus on the physiological function of PSCA and the mechanism of rs2294008.