The value of p16 and death-associated protein kinase methylation and autofluroscene spectrum analysis of gastric juice in diagnosing gastric carcinoma / 中华消化杂志

ABSTRACT

Objective To explore the feasibility of detecting death-associated protein(DAP) kinase promoter hypermethylation in the tumor tissues and plasma of patients with gastric adenocarcino- ma,and to evaluate the effect of DNA hypermethylation and autofluroscene spectrums of gastric juice on diagnosing gastric carcinoma.Methods Primary tumor tissues and plasma and gastric juice of 50 patients with gastric adenocarcinoma were collected.Gastric mucosa tissue,plasma and gastric juice of 20 patients with chronic superficial gastritis and 20 patients with benign gastric ulcer and 30 patients with chronic atrophic gastritis were collected as controls.After sodium-bisulfite treatment,extracted DNA was amplified for DAP kinase promoter hypermethylation by methylation-specific polymerase chain reac- tion.At the same time the gastric juice autofluroscene spectrums(the excitation wavelength was 288 nm,whereas the range of emission wavelength was 300-800 nm)were detected.Results Among the samples from 50 patients,p16 and DAP kinase hypermethylation were detected in 74.4% and 68.1% of tumor tissues,52.0% and 58.0% of plasma,58.6% and 76.0% of gastric juice.No hypermethylation was detected in samples of chronic superficial gastritis and serum of patients with gastric ulcer.Among the patients with gastric ulcer,p16 and DAP kinase hypermethylation were detected in 10.0% and 20.0% of tissues,5.0% and 15.0% of gastric juice.Among the samples from 30 patients with chronic atrophic gastritis,p16 and DAP kinase were detected in 10.0% and 23.3% of tissues,3.3% and 3.3% of sera,3.3% and 20.0% of gastric juice.The intensity of gastric juice autofluroscence spectrums of patients with gastric carcinoma was much higher than those in controls.The sensitivity of p16 and DAP kinase hypermethylation and autofluorescence spectrums together were 95.6% and 97.8% respectively.Con- clusions Promoter hypermethylation of the p16 and DAP kinase gene detected in plasma and gastric juice consists with that in primary tumor tissues of patients with gastric adenocarcinoma.The combination of DNA hypermethylation and autofluorescence spectrum has a good future in diagnosing gastric carcinoma.