[Detection of MG7 antigen expression in predicting high-risk in gastric cancer by automatic image analysis]

To study the predictive value of gastric cancer monoclonal antigen (MG7-Ag) in detecting atypical hyperplasia of gastric mucosa, its expression in 72 cases of the illness with follow-up was determined quantitatively by computer-aided image analysis system with immunohistochemical stain for MG7 antibody. Critical value of MG7-Ag expression for high-risk in gastric cancer was explored preliminarily by Youden index and receiver operator characteristic curve. Results of immunohistochemical stain showed there were 24 with positive expression (70.6%) in 34 cancerous cases, and only seven in 38 non-cancerous cases (18.4%), with a significant difference. Image analysis showed an average MG7-Ag density equal to or greater than 0.19 was regarded as the critical value for high-risk in gastric cancer, which could be used to discriminate atypical hyperplasia from canceration, with a sensitivity of 82.4%, a specificity of 78.9%, and an accuracy of 80.6%. Thus, it could be concluded that MG7-Ag expression correlated closely with canceration of gastric atypical hyperplasia, positive MG7-Ag expression in gastric mucosa of patients with atypical hyperplasia, especially in cases with a density of equal to or greater than 0.19, was an indicator for high risk in canceration. If they are put under strict follow-up, early detection of gastric cancer will be improved.