Objective:To analyze the expressions of minichromosome maintenance protein 4(MCM4) and proliferating cell nuclear antigen (PCNA) in gastric cancer tissues, to explore the relationship between MCM4/PCNA and gastric cancer, and to investigate the possibility of MCM4/PCNA as a potential biomarker for gastric cancer.Methods:Bioinformatics methods were used to analyze the mRNA expressions of MCM4 and PCNA in gastric cancer tissues and adjacent normal tissues. The clinicopathological data of 69 patients with gastric cancer who underwent surgery were retrospectively analyzed. The expression levels of MCM4 and PCNA in gastric cancer tissues and adjacent normal tissues were detected by immunohistochemistry, and their relationship with the clinicopathological characteristics of gastric cancer patients was analyzed.Results:The mRNA levels of MCM4 and PCNA in gastric cancer tissues are significantly higher than those in adjacent normal tissues (all P<0.05). The expression of MCM4 is correlated with the tumor size of gastric cancer ( P=0.037), but there is no significant correlation with gender, age and tumor grade (all P>0.05). Both MCM4 and PCNA proteins are highly expressed in gastric cancer patients. Conclusions:The expression levels of MCM4 and PCNA have a clear correlation with the occurrence of gastric cancer. MCM4 and PCNA are expected to be potential biomarkers for the diagnosis and treatment of gastric cancer.