Abstract: Abstract: Objective　To investigate the expression and biological effects of vitamin B2 in gastric cancer. Methods　Thirty-nine patients with gastric carcinoma (gastric cancer group) and 40 healthy controls (control group) were collected in this study. The serum expressions of vitamin B2 were detected in the two groups. The relationship between the level of vitamin B2 and the clinical pathological characteristics of gastric cancer patients was analyzed. Human gastric cancer MGC-803 cells were cultured and treated with 0 μmol/L, 10 μmol/L, 25 μmol/L, 50 μmol/L and 100 μmol/L vitamin B2 respectively. Glucose, lactic acid and succinate dehydrogenase levels were detected by biochemical kit. The mRNA expressions of  HKⅡ, PKM2 and GLUT1 were detected by qPCR. The cell proliferation was detected by CCK-8. Moreover, the cell apoptosis was detected by flow cytometry. Results　Compared with control group, the serum expression of vitamin B2 was significantly decreased in gastric cancer group (207.85 μg/L±39.71 μg/L vs. 246.07 μg/L±45.43 μg/L, P＜0.05). The serum expression of vitamin B2 was related with tumor TNM staging and the differentiation degree in patients with gastric cancer (P＜0.05). Compared with 0 μmol/L group, glucose consumption and lactate production were significantly decreased, while the content of succinate dehydrogenase was increased in 25 μmol/L, 50 μmol/L and 100 μmol/L groups (P＜0.05). Compared with 0 μmol/L group, HKⅡ, PKM2 and GLUT1 mRNA expressions were significantly decreased in 25 μmol/L, 50 μmol/L and 100 μmol/L groups (P＜0.05). Compared with the control group, the cell proliferation activities were decreased in turn in vitamin B2, Apatinib and combination groups (P＜0.05). Moreover, the combination could further reduce the cell proliferation activity (P＜0.05). Compared with the control group, the cell apoptosis rates were increased in turn in vitamin B2, Apatinib and combination groups (P＜0.05). Conclusion　The serum vitamin B2 levels decrease in patients with gastric cancer. The combination of vitamin B2 and apatinib could improve the anti-tumor effect on gastric cancer. 

Key words: riboflavin, stomach neoplasms, carcinoma, cell line, tumor, glycolysis, oxidative phosphorylation, apatinib