Expression of Kriippel-like factor 4 protein in esophageal squamous cell carcinoma and its clinical significance

Abstract

Objective To investigate the expression of Kriippel-like factor 4 （KLF4） protein in esophageal squamous cell carcinoma （ESCC） tissues and to explore its correlation with clinical pathological features as well as prognosis. Methods The expression of KLF4 protein in cancer tissues and normal esophageal tissues from surgical paraffin specimens of 98 thoracic ESCC cases with complete clinical, pathological and follow-up date were detected by immunohistochemistry. The expression of KLF4 at protein level in 20 freshly surgical esophageal cancer tissues and normal esophageal mucous tissues were examined by Western blot. The relation between the expression of KLF4 protein, clinicopathological characteristics and prognosis was analyzed, t-test was used for measurement data analysis. Chi-square test was performed to analyze the correlation between KLF4protein expression and clinicopathological features. Survival analysis was analyzed by the Kaplan-Meier method. The comparisons of survival rates were analyzed by Log-rank test. Results The positive rate of KLF4 protein expression in normal esophageal tissues and ESCC tissues was 82.7% （81/98） and 43.9% （43/98）, respectively, the difference was statistically significant （g2= 31. 701, P〈0.01）. The expression of KLF4 at protein level in 20 cases of fresh esophageal cancer tissues and normal esophageal mucosa tissues was 0. 576 -F 0. 050 and 0. 684 - 0. 095, respectively, the difference was statistically significant （t=4. 932,P%0.01）. The expression of KLF4 at protein level was correlated with lymph node metastasis and TNM stage （Z2 =10. 871 and 6. 482,P=0. 001 and 0. 039）, however not correlated with gender, age, location, tumor size, degree of differentiation and the depth of invasion （Z2=0. 214, 3. 442, 5. 748, 0. 891, 0. 013 and 1. 479,P=0. 644, 0. 064, 0. 056, 0. 345, 0. 911 and 0. 477）. In 98 patients, the 5-year survival rate of cases with KLF4 protein positive expression and negative expression was 48.80% and 25.5 % and the median survival period was 55 months and 26 months, the differences were statistically significant （x2 = 5. 747 and 4.493, P = 0.017 and 0. 034）. Conclusion KLF4 as a tumor suppressor gene may play an important role in the genesis, development and metastasis of ESCC, and may become a biological indicator of the severity and prognosis in ESCC. Key words: Esophageal neoplasms; Carcinoma, squamous cell; GKLF protein; Immuno-histochemistry; Blotting, Western; Prognosis