Abstract: Background and purpose: Peroxiredoxin Ⅱ (PrxⅡ) has the activity of peroxidase. The relevant studies found it played an important role in gastric cancer. This study aimed to investigate the expression of PrxⅡ in human gastric cancer tissues and cells, analyze its relationship with clinicopathological characteristics, and explore the relationship between PrxⅡ and the prognosis and the development of gastric cancer. Methods: The expression of PrxⅡ mRNA and protein in gastric cancer tissues and the paired adjacent normal tissues from 45 patients was detected by real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and Western blot. The same methods were used to detect the expression of PrxⅡ mRNA and protein in GES-1, MGC-803, MKN-45 and MKN-28. Tissue microarray and immunohistochemistry were used to detect the expression of PrxⅡ protein in gastric cancer tissues and the paired adjacent normal tissues from 116 patients. The relationship between the results and clinicopathological characteristics was analyzed. The prognosis was analyzed. Results: According to results of RTFQ-PCR and Western blot, we found that PrxⅡ mRNA and protein in gastric cancer tissues were significantly higher than that in adjacent normal tissues (P<0.05). PrxⅡ mRNA and protein in gastric cancer cells were higher than that in normal gastric cells (P<0.01). Immunohistochemistry revealed that the expression of PrxⅡ protein in gastric cancer tissues (76.7%) was also significantly higher (P<0.01) than that in adjacent normal tissues (30.1%). The expression of PrxⅡ protein is significantly related to tumor size, histological differentiation, depth of invasion, TNM stage and lymph node metastasis (P<0.05), but had no significant relationship with the gender, age, tumor location and distant metastasis. Survival in patients with higher PrxⅡ expression significantly shorter than in those with lower expression (P<0.01). PrxⅡ is an independent prognostic factor of gastric cancer (P<0.05). Conclusion: PrxⅡ promotes the development of gastric cancer. It is one of the adverse prognostic factors of gastric cancer and may serve as a new therapeutic target for gastric cancer.

Key words: Peroxiredoxin Ⅱ, Gastric cancer, Real-time fluorescent quantitative polymerase chain reaction, Tissue microarray