Abstract 644: Identification of a novel hypermethylated tumor suppressor gene in human bladder cancer and its implication in non-invasive cancer detection using voided urine.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Bladder cancer is the sixth most common cancer in the world and the incidence is particularly high in southwestern Taiwan. Although bladder cancer patients have a low mortality rate, long term follow-up with repeated cystoscopy is required due to the high recurrence nature of the tumor. Therefore, a non-invasive detection assay is urgently required for bladder cancer patients. Aberrant promoter hypermethylation which is considered as a hallmark of cancer for over a decade, plays an important role in controlling cancer progression. Nevertheless, detection of promoter hypermethylation in bodily fluid has been implicated as a non-invasive and sensitive tool for cancer diagnosis. In this regard, by using illumina 27K CpG island methylation array, we identified a novel gene that are hypermethylated in 7 bladder cancer patient samples but not in primary normal human urothelim. In vitro promoter methylation assay and epigenetic treatment confirmed that the expression of this gene is epigenetically controlled in bladder cancer cell lines. Bisulphite pyrosequencing demonstrated a significant correlation between higher methylation level of this gene and cancer grade (P<0.01) and recurrence free survival (P<0.05) in bladder cancer patient samples (n=100). To investigate the diagnostic potential of this novel epigenetic marker in non-invasive cancer detection, we performed qMSP assay in voided urine samples from bladder cancer patients (n=27) as well as normal healthy control (n=19). The sensitivity and specificity of this gene in cancer detection is 42.3% and 100% respectively. The sensitivity can increase to 93.3% when using combination of this gene and our previously identified epigenetic markers (IRF8, p14, sFRP1). Re-expression of this gene in bladder cancer cell line inhibited cancer growth in soft agar colony formation assay and invasion assay. In conclusion, this gene may be a potential tumor suppressor in bladder cancer and its potential in non-invasive diagnosis of bladder cancer using voided urine warrants further investigation. Citation Format: Chia-Ming Yeh, Pi-Che Chen, Yu-Hsin Chen, Lin-Chien Hung, Yi-Ting Wang, Ming-Hsuan Tsai, Martin MS Huang, Cheng-Huang Shen, Cheng-Da Hsu, Michael WY Chan. Identification of a novel hypermethylated tumor suppressor gene in human bladder cancer and its implication in non-invasive cancer detection using voided urine. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 644. doi:10.1158/1538-7445.AM2013-644