Expressions and clinicopathological significances of BMI-1 and PADI4 in esophageal squamous cell carcinoma

Abstract

Objective To evaluate the expression levels of peptidylarginine deiminase 4 (PADI4) and B-cells pecific Moloney leukemia virus insert site-1 (BMI-1) in esophageal squamous cell carcinoma (ESCC) tissues and pericarcinous tissues. To explore the function and clinical significance in the development of ESCC and their association. Methods The expression levels of PADI4 and BMI-1 were measured by immunohistochemistry, Western blotting and quantitative real time PCR in ESCC tissues and pericarcinous tissues from 86 patients. The relationships between the expressions of PADI4 and BMI-1 and the clinicopathologic characte-ristics were analyzed. Results The immunohistochemistry showed that the expressions of PADI4 and BMI-1 in ESCC tissues (68.6% and 73.3%) were significantly higher than those in pericarcinous tissues (37.2% and 30.2%, χ2=17.011, P=0.000; χ2=31.876, P=0.000). Western blotting indicated that the levels of PADI4 and BMI-1 were higher than those in pericarcinous tissues (0.919±0.098 vs. 0.718±0.103, t=2.462, P=0.021; 0.975±0.074 vs. 0.717±0.071, t=2.640, P=0.014). The expressions of BMI-1 and PADI4 mRNA in ESCC tissues were higher than those in pericarcinous tissues, but the differences were not statistically significant (0.091±0.005 vs. 0.038±0.002, t=1.701, P=0.101; 0.114±0.075 vs. 0.048±0.003, t=1.499, P=0.146) by the quantitative real time PCR. The expression of PADI4 was correlated with lymph node metastasis (χ2=5.771, P=0.016), depth of invasion (χ2=6.672, P=0.010) and clinical stage (χ2=5.771, P=0.016). The BMI-1 gene expression had a correlation with lymph node metastasis (χ2=7.176, P=0.007), the differentiation degree (χ2=13.787, P=0.001) and clinical stage (χ2=7.176, P=0.007). In addition, there was a positive correlation between PADI4 and BMI-1 expression in ESCC by immunohistochemistry and quantitative real time PCR (r=0.214, P=0.047; r=0.534, P=0.005). Conclusion The expression levels of PADI4 and BMI-1 are significantly higher in ESCC compared to pericarcinous tissues. PADI4 and BMI-1 are positively correlated and may contribute to the diagnosis and prognosis of the ESCC. Key words: Esophageal neoplasms; Peptidylarginine deiminase 4; B-cells pecific Moloney leukemia virus insert site-1