Background: E3 ubiquitin ligase Ring finger protein 180 (RNF180) has been identified as a novel tumor suppressor in gastric cancer and the methylated CpG site count of RNF180 DNA promoter can predict the prognosis for gastric cancer patients.
Objective: In the previous study, we demonstrated that methylated CpG site count of RNF180 DNA promoter was significantly associated with the survival of patients with gastric cancer using the bisulfite genomic sequencing (BGS) in the gastric cancer tissue with five clones per sample. It was so complicate for each patient underwent the BGS detection with clones. It is important to explore a simple, rapid and accurate method to detect methylated CpG site count to predicting the prognosis for gastric cancer patients.
Methods: At present study, we detected hypermethylated and hypomethylated CpG site count of RNF180 DNA promoter in samples of 480 gastric cancer patients by direct bisulfite sequencing.
Results: We found that patients who possessed seven or less hypermethylated CpG sites of RNF180 DNA promoter had much better survival (p= 0.008), which was similar to our previous research results by using the BGS with clones. With the multivariate survival analysis, we found that T stage, N stage and hypermethylated CpG site count of RNF180 DNA promoter were the independent predictors of prognosis for gastric cancer patients.
Conclusions: hypermethylated CpG site count of RNF180 DNA promoter for evaluating the prognosis of gastric cancer was reasonable by using the direct bisulfite sequencing.
Keywords: Ring finger protein 180; direct bisulfite genomic sequencing; gastric cancer; methylation; prognosis.