Complex symptoms often make it difficult to choose optimized strategies suitable for gastric patients. Therefore, molecular markers are needed to assist doctor' s diagnoses. In this study, to determine if the mRNA levels of Th1 and Th2 cytokines in peripheral blood mononuclear cells (PBMC) of patients with gastric cancer were correlated with their various stages, gastric patients, patients with benign gastric disease, and heathy people were recruited for detection of cytokine mRNA levels. Only the relative levels in comparison with levels of each patient's own α-actin were subjected to further statistical analyses. We found that there were significantly more positive detection of IL-4, IL-6, IL-10 mRNA expression in stage III and IV than those in patients with gastic cancer in stage I and II. It was also found that IL-4, IL-6, IL-10 mRNA expression in patients with low-level differentiations possessed significantly higher positive detection ratios than patients with moderate or high-level differentiation. These results suggest that positive detection of IL-4, IL-6 and IL-10 mRNA may be useful as a molecular marker approach for distinguishing the stage II and III of gastric cancer, as well as low-level and moderate cancer differentiation.