Circulating promoter methylation status in gastric adenocarcinoma and esophageal square cell carcinoma.

The secreted frizzled-related protein 1 () gene plays an important role in carcinogenesis of digestive system cancer. Previous studies proved that circulating DNA promoter methylation may be a suitable biomarker for cancer patients. The aim of the present study was to investigate whether the promoter methylation status of serum is a potential biomarker for gastric adenocarcinoma (GAC) and esophageal square cell carcinoma (ESCC). The blood samples obtained from 42 GAC and 36 ESCC patients were detected for the promoter methylation status of by methylation-specific polymerase chain reaction. The control group included 42 benign gastrointestinal disease volunteers (24 benign gastric disease and 18 benign esophageal disease) and 20 healthy volunteers. Serum methylation was evident in 30.95% (13/42) GAC patients and 38.89% (14/36) ESCC patients, which is clearly higher compared to 8.33% (2/24) in benign gastric disease, 11.11% (2/18) in benign esophageal disease and 5% (1/20) in healthy volunteers (P<0.05). The association between the serum promoter methylation status and the clinical pathological features were further analyzed and methylation of the gene was significantly associated with age >60 years in GAC patients (P=0.027). However, no correlations between the methylation status and other clinicopathological parameters were found. In conclusion, the promoter was detected frequently in the serum of GAC and ESCC patients. The detection of circulating methylated in the serum may be a useful biomarker for upper gastrointestinal cancer patients.