Distinct DNA methylation epigenotypes in bladder cancer from different Chinese sub-populations and its implication in cancer detection using voided urine

Abstract

BackgroundBladder cancer is the sixth most common cancer in the world and the incidence is particularly high in southwestern Taiwan. Previous studies have identified several tumor-related genes that are hypermethylated in bladder cancer; however the DNA methylation profile of bladder cancer in Taiwan is not fully understood.MethodsIn this study, we compared the DNA methylation profile of multiple tumor suppressor genes (APC, DAPK, E-cadherin, hMLH1, IRF8, p14, p15, RASSF1A, SFRP1 and SOCS-1) in bladder cancer patients from different Chinese sub-populations including Taiwan (104 cases), Hong Kong (82 cases) and China (24 cases) by MSP. Two normal human urothelium were also included as control. To investigate the diagnostic potential of using DNA methylation in non-invasive detection of bladder cancer, degree of methylation of DAPK, IRF8, p14, RASSF1A and SFRP1 was also accessed by quantitative MSP in urine samples from thirty bladder cancer patients and nineteen non-cancer controls.ResultsThere were distinct DNA methylation epigenotypes among the different sub-populations. Further, samples from Taiwan and China demonstrated a bimodal distribution suggesting that CpG island methylator phentotype (CIMP) is presented in bladder cancer. Moreover, the number of methylated genes in samples from Taiwan and Hong Kong were significantly correlated with histological grade (P < 0.01) and pathological stage (P < 0.01). Regarding the samples from Taiwan, methylation of SFRP1, IRF8, APC and RASSF1A were significantly associated with increased tumor grade, stage. Methylation of RASSF1A was associated with tumor recurrence. Patients with methylation of APC or RASSF1A were also significantly associated with shorter recurrence-free survival. For methylation detection in voided urine samples of cancer patients, the sensitivity and specificity of using any of the methylated genes (IRF8, p14 or sFRP1) by qMSP was 86.7% and 94.7%.ConclusionsOur results indicate that there are distinct methylation epigenotypes among different Chinese sub-populations. These profiles demonstrate gradual increases with cancer progression. Finally, detection of gene methylation in voided urine with these distinct DNA methylation markers is more sensitive than urine cytology.

DNA methylation profiling in Barrett’s esophagus and esophageal adenocarcinoma reveals unique methylation signatures and molecular subclasses

“…This phenomenon was initially described in a subclass of colorectal tumors called "CIMP" (CpG island methylator phenotype), which are characterized by widespread hypermethylation of promoter CpG islands, resulting in the inactivation of several tumor suppressor genes. 39,40 CIMP subclasses have also been established in numerous other cancers within the last few years, including mantle cell lymphoma, 41 bladder, 42 glioma, 31 breast, 43 lung, 44 gastric, 45 hepatocellular 46 and melanoma. 47 In many of these cancer types, the CIMP group of tumors demonstrates a particular phenotype, such as increased aggressiveness (melanoma), a higher rate of recurrence (hepatocellular carcinoma), or a distinct histology (colon cancer).…”

DAPK Promoter Methylation and Bladder Cancer Risk: A Systematic Review and Meta-Analysis

“…Down regulation of DAPK expression by promoter methylation was observed in both tissue and cell lines of BCa [15, 16]. DAPK promoter methylation was detected in the urine and blood of BCa patients, making it a potential non-invasive diagnostic biomarker [17–19]. In addition, DAPK promoter methylation was associated with tumor stage and histological grade [16, 20–22].…”

Hypermethylation in bladder cancer: biological pathways and translational applications

“…Several members of the WNT/beta-catenin pathway have been reported to be frequently methylated in bladder cancer, including the secreted frozzled-related proteins (SFRP) such as members SFRP1 [57,77,115,123,125], SFRP2 [77,123,125], SFRP4-5 [46,77,[123][124][125], or the Wnt inhibitory factor-1 (WIF1) [123][124][125][126]. These studies highlight the targetable role of WNT pathway in bladder cancer [123][124][125][126][127].…”

“…An increasing number of hypermethylation individual events at single gene loci are indicating differential outcomes among bladder cancer patients. Among the genes most frequently studied, for example, hypermethylation of the genes encoding such as CDKN2A [72,73,78], DAPK [68,72,97,98], RASFF1A [72,73,86,115], CDH1 [72,73,86,95], SFRPs [123,125], RUNX3 [129,132], or myopodin [134,135], among others, has strongly been linked to poor outcomes in tissue specimens (Table 1) [34][35][36][37][38][39][40]. Combinations of tumor-suppressor genes have also been utilized for this purpose [58,59].…”

“…The initial studies have tried to evaluate whether urinary methylomes may serve for the diagnosis of the disease ( Table 1). The most studied genes reporting to play a potential diagnostic role with global accuracies over 65% in urinary specimens include CDKN2A [57, 58, 60, 67, 79, 83-85, 108, 115, 127], CCND2 [83], GSTP1 [58, 83-85, 108, 131], APC [57, 60, 83-85, 108, 142, 143], BRCA1 [58,131], RASFF1A [60, 71, 74, 79, 83-85, 105, 108, 115, 131, 142, 143], BCL2 [60,74,101,131,142], CDH1 [60,84,105,108,127], SFRP1 [57,115,124,127,140], SFRP2,4,5 [124,140], WIF1 [60,124,140,142], myopodin [134], PMF1 [137], and RARB [57,58,60,67,84,85,105,108,139,140], among others. These studies were initially performed by MS-PCR in qualitative or quantitative fashion modalities [67, 71, 74, 79, 83-85, 101, 105, 108, 110, 115, 119, 124, 126, 131, 139, 140, 142] and currently it is feasible by comprehensive multiplexed analyses such as by MS-MLPA …”