Detection of Serum Gastric Cancer-Associated MG7-Ag from Gastric Cancer Patients Using a Sensitive and Convenient ELISA Method

Purpose: To seek a high sensitive and convenient method for early diagnosis of gastric cancer by testing MG7-Ag in serum of gastric cancer patients and some other control groups using a convenient ELISA method. Experiment Design: The expression of serum MG7-Ag was detected in 116 preoperative gastric cancer patients, 63 postoperative gastric cancer patients, 78 precancerous lesion patients, 50 healthy blood donors and patients of other cancers by a convenient ELISA method. For comparison, serum CEA, CA 50, CA 19-9 and TAG-72 were also detected in preoperative gastric cancer patients. Meanwhile, the expression of MG7-Ag was detected by immunohistochemical analysis in the groups of patients with gastric cancer or precancerous lesion mentioned above. Results: The positive rate of Mg7-Ag determined by ELISA was 83. 6% of preoperative gastric cancer patients, 54.8% of lung cancer patients, 45.5% of rectal cancer patients, 17.6% of colonic cancer patients, 14.2% of breast cancer patients, 47.6% of postoperative gastric cancer patients, 12.8% of precancerous lesions patients and 0% of healthy blood donors, respectively. The sensitivity of ELISA (83.6%) was found to be similar with that of immunohistochemistry (94%, p > 0. 01), while the false positive rate was lower (12.8% vs. 51.3%). MG7-Ag expression level in gastric cancer was correlated with tumor differentiation (p < 0. 01) and pathological stage (p < 0. 01). Conclusion: This ELISA method may be a non-invasive candidate method for screening of large population with high risk of gastric cancer.