Screening and Triage Test for Early Detection of Gastric Cancer (STEAD-GC): A noninvasive trial for early detection of gastric cancer.

Abstract

17 Background: Gastric cancer (GC) is the second leading cause of cancer-related deaths worldwide. Previously, we identified a potential biomarker for non-invasive detection of GC, the DNA methylation of the promoter region of Reprimo, a p53-dependent G2 arrest mediator candidate (Clin Cancer Res 2008;14:6264-9). Furthermore, we developed a quantitative assay (MethyLight) for a mass screening of GC (DDW2011-1029128). Here we reported the preliminary findings of our ongoing prospective trial STEAD-GC (Screening and Triage test for Early Detection of Gastric Cancer) which is being conducted in Chile, a country with a high mortality rate for GC. Methods: Twenty GC cases (tumor, non-tumor tissues and plasma samples) and 41 symptomatic chronic gastritis cases (29 tissues and 12 pairs of tissue and plasma samples) were evaluated for Reprimo levels by MethyLight after DNA extraction and bisulfite conversion. Results: Concentrations of DNA were similar in both groups (Avg 32.2 ng/ml [range: 8.9-70.8 ng/ml]). The average DNA levels of Reprimo were higher in GC [964,215 copies/ml, 539,593 copies/ml and 80,113 copies/ml in tumor, non-tumor and plasma, respectively] but lower in symptomatic chronic gastritis [137,721 copies/ml and 8,387 copies/ml, tissue and plasma, respectively]. Methods: Twenty GC cases (tumor, non-tumor tissues, and plasma samples) and 41 symptomatic chronic gastritis cases (29 tissues and 12 pairs of tissue and plasma samples) were evaluated for Reprimo levels by MethyLight after DNA extraction and bisulfite conversion. Conclusions: By using our previous cut-off of 15,125 copies/ml, our method correctly identified 10 out of 12 gastritis cases and 16 out of 20 GC cases (p value <0.001). Our data confirms our non-invasive method for early detection of GC may be suitable for a mass screening of GC.