Methylation status of the T-cadherin gene promotor in peripheral blood mononuclear cells is associated with HBV-related hepatocellular carcinoma progression.

DNA methylation is one of the epigenetic mechanisms to regulate gene expression and frequently occurs in human cancer cells. T-cadherin (CDH13) is a new member of the cadherin superfamily and possesses multiple functions. Our study included 26 normal controls (NCs), 65 chronic hepatitis B patients (CHB), 14 liver cirrhosis patients (LC) and 157 hepatocellular carcinoma patients (HCC). We mainly focused on the mRNA expression and methylation status of CDH13 in peripheral blood mononuclear cells (PBMCs), which were detected by semi-quantitative real-time polymerase chain reaction (RT-qPCR) and methylation-specific polymerase chain reaction (MSP) respectively. The CDH13 mRNA level was lower in HCC, especially in early-stage of HCC than in NCs and CHB groups (p < 0.05). Methylation frequency of the CDH13 promoter was significantly higher in HCC patients than in the NCs and CHB groups (67.52 % vs 0.00 %, p < 0.001, 67.52 % vs 52.31 %, p < 0.05, respectively). CDH13 mRNA level was significantly and relatively lower in methylated groups than in unmethylated groups among the whole participants. The methylation level of CDH13 promoter in HCC might be influenced or partly influenced by some critical factors such as TBil, ALB and AFP (p < 0.05). As an important factor in signaling pathway regulating by CDH13 to promote carcinogenesis, JNK level was significantly higher in HCC which had a higher methylation frequency than in NCs, CHB and LC (p < 0.05). Furthermore, the combination of the methylated CDH13 level and AFP level showed a better score: AUC = 0.796 (SE = 0.031, 95 %CI 0.735-0.857; p < 0.001) in male and AUC = 0.832 (SE = 0.057, 95 %CI 0.721-0.944; p < 0.001) in female compared to AFP alone for diagnosing HCC from NCs, CHB and LC. The methylation of CDH13 promoter was an independent predictor for assessing the prognosis of HCC patients (r=-1.378 p < 0.05). In conclusion, hypermethylation of CDH13 in PBMCs was associated with the underexpression of mRNA and the high risk of HCC. The methylation status of the CDH13 promoter in PBMCs was a potential noninvasive biomarker to predict the prognosis of HCC patients.