Abstract: OBJECTIVE To investigate the expression of macrophage migration inhibitory factor（MIF） protein, P-glycoprotein（P-gp） and Fas ligand（FasL） protein in gastric mucosa of gastric cancer patients with Helicobacter pylori（Hp） infection and analyze their significance.METHODS Totally 159 gastric cancer patients whose gastric mucosa tissues were retained in pathology department of Hai’an Hospital Affiliated to Nantong University from Jun 2019 to Jun 2020. The Hp infection was determined by Warthin-Starry silver staining method, the patients were divided into the Hp-positive group with 97 cases and the Hp-negative group with 62 cases, totally 30 patients whose tissues were more than 5 cam apart from the margin of cancer tissues and verified as normal gastric mucosa by pathological examination were chosen as the normal mucosa group. The expression of MIF, P-gp and FasL in gastric mucosa tissues was determined by using immunohistochemistry, and the significance of expression in the gastric mucosa tissues of the gastric cancer patients with Hp infection was observed.RESULTS The positive rates of MIF, P-gp and FasL of the Hp-negative group and the Hp-positive group were significantly higher than those of the normal mucosa group, the positive rates of MIF, P-gp and FasL of the Hp-positive group were significantly higher than those of the Hp-negative group（P＜0.05）. The expression of MIF, P-gp or FasL was not associated with gender, age and diameter of tumor of the patients in the Hp-positive group but was associated with the TNM stage, degree of differentiation, depth of invasion and lymph node metastasis. The positive rates of MIF, P-gp and FasL were relatively high among the patients with stage III plus IV, moderate and mild differentiation, T3 plus T4 infiltration and lymph node metastasis（P＜0.05）. Receiver operation characteristic（ROC） curve analysis showed that the value of the joint detection of MIF, P-gp and FasL was significantly higher in prediction of the gastric cancer patients with Hp infection than the single detection（P＜0.05）.CONCLUSION The expression levels of MIF, P-gp and FasL are significantly elevated in the gastric mucosa tissues of the gastric cancer patients with Hp infection and are associated with multiple clinical features, and they can be served as sensitive indexes for prediction of Hp infection-induced gastric cancer.