Expression of the Nrf2 and Keap1 proteins and their clinical significance in osteosarcoma

Objective: To investigate the expression and clinical significance of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in osteosarcoma tissue. Methods: The data of 102 osteosarcoma patients who underwent surgical treatment at our hospital from June 2000 to March 2009 were collected. The expression levels of the Nrf2 and Keap1 proteins in osteosarcoma tissue and normal peritumour tissues were detected by immunohistochemistry, and the relationship between the expression level and the clinical and pathological features as well as the prognosis was explored. Results: The nuclear expression rate of Nrf2 was 77.5% in osteosarcoma tissue, which was significantly higher than the rate in normal peritumour bone tissue (9.8%) (P < 0.05). The expression rate of the Keap1 protein in osteosarcoma tissue was 13.7%, which was significantly lower than the rate in normal peritumour tissue (80.4%). In addition, Nrf2/Keap1 expression was unrelated to patient gender and age, tumour site, and histological type and was related to metastasis and patient response to chemotherapy (P < 0.05). The five-year survival rate was significantly lower in patients with positive Nrf2 expression than in those with negative Nrf2 expression (p = 0.023), and it was significantly higher in patients with positive Keap1 expression than in those with negative Keap1 expression (P = 0.018). Conclusion: The expression of Nrf2-Keap1 is abnormal in osteosarcoma tissue and shows significant clinical relevance for determining the prognosis of osteosarcoma.