Investigation on correlations of serum IL-26 with diagnosis and staging of gastric cancer.

Purpose: To investigate the correlations of interleukin-26 (IL-26) with the diagnosis and pathological stage of gastric cancer by comparing the serum IL-26 levels in patients with different pathological stages of gastric cancer.

Methods: A total of 302 patients with gastric cancer hospitalized in Chinese PLA General Hospital from April 2015 to October 2017 were selected and divided into 4 groups according to the seventh edition of the staging guidance for gastric cancer of American Joint Committee on Cancer (AJCC), including stage I (n=75), stage II (n=73), stage III (n=125) and stage IV (n=29). Meanwhile, patients with benign stomach diseases admitted to the hospital during the same period were enrolled as controls (n=100). The differences in the levels of IL-26 and tumor markers between benign stomach diseases and gastric cancer and among stages were compared, and the correlations of IL-26 with the occurrence and different pathological stages of gastric cancer were analyzed.

Results: The serum IL-26 level in the patients with gastric cancer was remarkably higher than that in benign stomach disease group [(267.14±20.39) vs. (172.12±13.38) pg/mL, p<0.05], which was similar to the change trends of tumor markers such as carbohydrate antigen (CA) 724. The serum IL-26 level in the gastric cancer tissues was gradually elevated with the increase in clinical stage of gastric cancer [stage I: (213.05±19.05) pg/mL, stage II: (244.98±24.14) pg/mL, stage III: (278.45±20.68) pg/mL and stage IV: (291.73±15.62) pg/mL; p<0.05]. The serum IL-26 level had positive correlations with gastric cancer (r=0.528, p<0.001). Logistic regression analysis indicated that serum IL-26 was still an independent risk factor for the occurrence of gastric cancer after age, gender, carcinoembryonic antigen (CEA), CA125 and other risk factors were adjusted [odds ratio (OR)=1.216, P=0.002].

Conclusions: The serum IL-26 level is closely correlated with gastric cancer and its clinicopathological stages, which is of important value for determination of the occurrence and development of the disease.