A sensitive and convenient enzyme-linked immunosorbent assay method in serum MG7 antigen detection in gastric cancer

Abstract

Objective To explore a highly sensitive and highly specific method to detect the serum MG7 antigen (Ag) level for early gastric cancer diagnosis. Methods The serum MG7-Ag level was detected by enzyme-linked immunosorbent assay (ELISA) method in 116 preoperative gastric cancer patients, 63 postoperative gastric cancer patients, 41 patients with precancerous lesion, 37 patients with precancerous diseases, 50 healthy individuals and 281 patients with other cancers. Meanwhile, the expression of MG7-Ag was also examined with immunohistochemistry in patients with gastric cancer or precancerous lesion. Chi-square test was used for comparing positive rates of the two detection methods. Results The positive rate of MG7-Ag determined by ELISA was 83.6%(97/116) of preoperative gastric cancer patients, 45.2%(28/62) of lung cancer patients, 45.5%(20/44) of rectal cancer patients, 17.6%(12/68) of colonic cancer patients, 14.2%(6/42) of breast cancer patients, 47.6%(30/63) of postoperative gastric cancer patients, 19.5%(8/41) of patients with precancerous lesions, 5.4%(2/37) of patients with precancerous diseases and 0 of healthy individuals. The sensitivity of ELISA (83.6%) was similar with that of immunohistochemistry (94.0%)(P>0.05). However, the false positive rate of ELISA (12.8%) was lower than that of immunohistochemistry (51.3%)(χ2=26.491, P<0.01). There was statistically significant difference in MG7-Ag expression in gastric cancer with different clinical stages (χ2=15.564, P<0.01). Conclusion This ELISA method might be a non-invasive screening method for population with high risk of gastric cancer. Key words: Enzyme-linked immunosorbent assay; Stomach neoplasms; MG7-Ag; Sensitivity and specificity