Expression of growth inhibitory factor 2 in human esophageal squamous cell carcinoma and clinical significance

Objective To investigate the expression of growth inhibitory factor 2 (ING2) in esophageal squamous cell carcinoma (ESCC), and explore its correlation with lymphatic metastasis and prognosis. Methods The expression of ING2 in 63 cases of ESCC tissues and 63 cases of normal tissues was detected by immunohistochemistry. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to examine the expression of ING2 mRNA in fresh tumoral and normal tissues. Results The ING2 positive staining was predominantly localized in both nucleus and cytoplasm of cancer cells, but weakly in nucleus of normal epithelial cells only. The expression of ING2 protein and mRNA was significantly higher in ESCC tissues than in normal tissues (P=0.001). Moreover, the expression level of ING2 protein in ESCC tissues was significantly correlated with grade (P=0.010) and lymph node metastasis (P=0.001). Cox regression analysis revealed that ING2 expression level (P=0.042) and lymph node metastasis (P=0.000) were independent prognostic factors of ESCC. Conclusion ING2 is overexpressed in ESCC tissues. High expression of ING2 correlates with pathological grades, lymphatic metastasis and unfavorable survival in ESCC. Key words: Esophageal neoplasms; Squamous cell; Growth inhibitory factor 2; Metastasis; Prognosis