Background and objective: Gene associated with retinoid-interferon-induced mortality-19 (GRIM-19) is one of the death-related genes. Its overexpression could suppress proliferation and promote apoptosis of tumor cells. This study was to investigate the expression and clinical significance of GRIM-19 in primary non-small cell lung cancer (NSCLC).
Methods: The expression of GRIM-19 in 49 specimens of NSCLC with corresponding adjacent normal lung tissues was examined by immunohistochemistry. The cellular distribution of GRIM-19 was observed under laser scanning confocal microscope.
Results: GRIM-19 was dominantly located in the cytoplasm of normal lung cells but enriched in the nuclei of cancer cells. The result was verified by laser scanning confocal microscopy. The positive rate of GRIM-19 was significantly higher in normal lung tissues than in NSCLC (93.8% vs. 55.1%, P<0.05). The protein level of GRIM-19 in NSCLC was reduced by 24.3% of that in normal lung tissues (0.22+/-0.01 vs. 0.29+/-0.02, P<0.05). The positive rates of GRIM-19 were 78.6% in stage I NSCLC, 48.1% in stage II NSCLC, and 12.5% in stages III-IV NSCLC. The expression of GRIM-19 was negatively correlated to clinical stage (rs=-0.428, P<0.05).
Conclusion: GRIM-19 expression is down-regulated along the clinical development of NSCLC, and transfers from cytoplasm to nucleus.