Analysis Of The Methylated Status Of PAX5,RNF180 And PCDH10 Genes From Plasma In Gastric Cancer

Objective To investigate the expression of PAX5,RNF180 and PCDH10 gene promoter methylation in plasma,and to analyze the relationship between the expression and the clinical pathological characteristics of gastric cancer.Furthermore,to determine the ability of the three genes to predict the occurrence of gastric cancer.Methods Plasma samples were collected from 109 patients with gastric cancer and 30 healthy volunteers from August 2015 to August 2016 in Tianjin Cancer Hospital And Institute.The DNA extracted from the plasma samples was used to detect the DNA promoter methylation status of PAX5,RNF180 and PCDH10 using methylated specific PCR(MSP).Then the clinical and pathological indexes were analyzed statistically.Results 1.MSP results showed that: In 109 cases of gastric cancer patients,37 had PAX5 gene methylation,the methylation rate is 33.94%;38 had RNF180 gene methylation,the methylation rate is 34.86%;33 had PCDH10 gene methylation,the methylation rate is 30.28%.Correspondingly,in 30 cases of normal person,the methylation rate were 6.67%,10% and 13.33%.Statistical analysis showed that the methylation rate of PAX5 and RNF180 genes was significantly different between the gastric cancer group and the normal group(p <0.01),but there was no significant difference for PCDH10 gene(p>0.05).2.The PAX5 gene promoter methylation in plasma was associated with age of patients with gastric cancer(p <0.05),but not correlated with gender,tumor size,Borrmann classification,T stage,N stage,TNM stage and soft tissue metastasis(p>0.05).While,the RNF180 and PCDH10 gene promoter methylation in plasma was associated with N stage,but not correlated with other factors.3.The presence of gastric cancer was associated with PAX5 gene promoter methylation(OR,3.528;95%CI,0.542-0.861;p = 0.017)and RNF180 gene promoter methylation(OR,2.647;95%CI,1.080-6.487;p = 0.033).But there was nosignificant correlation between gastric cancer and PCDH10 gene promoter methylation(OR,1.540;95%CI,0.610-3.890;p = 0.361).95%CI and p-values of gastric cancer were predicted to be 4.40(1.82-10.65),0.0185 and 3.42(1.47-7.92),0.036,respectively in the methylation status of PAX5 and RNF180 gene promoters.In addition,when the PAX5 and RNF180 genes were co-detected,the OR(95%CI)5.57(2.13-14.57),p = 0.0012,which was significantly better than the two genes alone.However,the specificity(47.62%)was significantly lower than that of PAX5 alone(76.19%).Conclusion PAX5 and RNF180 genes are identified as representative hyper methylated genes in gastric cancer.Although the functional effects of methylation of PAX5 and RNF180 genes in gastric cancer have not been established,they have a high potential as a biomarker based on plasma testing.In addition,this study indicates that the combination test of PAX5 and RNF180 gene methylation may be a promising way to diagnose gastric cancer.