Abstract: Objective To detect the expressions of two protein factors hypoxia- inducible factor (HIF)- 1α and Helicobacter pylori (Hp) in gastric cancer in Mongolian and Han two nationalities respectively, and to explore the relationship of HIF-1α and Hp in the development of gastric cancer. Methods A modified Warthin-Starry (W-S) silver staining method was used to detect Hp infection in 27 Mongolian patients with gastric cancer and 30 Han patients with gastric cancer. Immunohistochemical (S-P) method and reverse transcription polymerase chain reaction (RT-PCR) method were used to detect protein and mRNA expressions of HIF- 1α in cancer tissue, paracancerous tissue and normal tissue samples. The relationship of HIF-1α protein and Hp expression was analyzed between gastric carcinoma tissue samples of Mongolian patient group and Han patient group. Results Hp infection rates were 81.5% (22/27) and 66.7% (20/30) in Mongolian and Han patients with gastric cancer. The difference in infection rate was not statistically significant between two groups of patients (χ2=1.608, P > 0.05). The positive expression levels of HIF-1α protein were 62.96% (17/27) and 70.00% (21/30) in gastric cancer tissue samples of Mongolian and Han groups. The relative expression levels of HIF-1α mRNA were 0.891 4±0.075 0 and 0.907 4±0.065 5. There was no significant difference in the HIF-1α mRNA expression between the two nationalities. No positive expressions of HIF-1α protein and mRNA were found in paracancerous tissue and normal tissue samples. There was a positive correlation in the positive expression of HIF- 1α protein and Hp infection in gastric cancer tissue samples of Mongolian and Han patient groups (rs =0.424 and 0.617, P < 0.05). Conclusion HIF-1α and Hp are pathogenic factors of gastric cancer. Hp and HIF-1α may promote the occurrence of gastric cancer together. The pathogenic mechanism of HIF-1α and Hp in gastric cancer may be the same for Mongolian and Han patients.

Key words: stomach neoplasms, hypoxia-inducible factor 1, alpha subunit, helicobacter pylori, immunohistochemistry, reverse transcriptase polymerase chain reaction, Han nationality, Mongolian nationality