Brief Articles
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. May 21, 2009; 15(19): 2389-2394
Published online May 21, 2009. doi: 10.3748/wjg.15.2389
Association between Bmi1 and clinicopathological status of esophageal squamous cell carcinoma
Xiao-Ting He, Xiu-Feng Cao, Lv Ji, Bin Zhu, Jin Lv, Dong-Dong Wang, Pei-Hua Lu, Heng-Guan Cui
Xiao-Ting He, Xiu-Feng Cao, Lv Ji, Bin Zhu, Jin Lv, Dong-Dong Wang, Pei-Hua Lu, Heng-Guan Cui, Nanjing Medical University, Affiliated Nanjing First Hospital, Department of oncology surgery, Oncology Center of Nanjing Medical University, Nanjing 210006, Jiangsu Province, China
Pei-Hua Lu, Surgical Department of Wuxi People’s Hospital, Wuxi 214002, Jiangsu Province, China
Author contributions: He XT participated in the design of study, acquisition, analysis and interpretation of data, manuscript writing and statistical analysis of data, revision of the manuscript; Cao XF substantially contributed to the conception and design of study, fund acquisition, administration and materials support; Ji L participated in the design of study, fund acquisition and technology support; Zhu B, Lv J, Lu PH, Wang DD and Cui HG provided supportive contributions.
Correspondence to: Xiu-Feng Cao, Nanjing Medical University, Affiliated Nanjing First Hospital, Department of oncology surgery, Oncology Center of Nanjing Medical University, Nanjing 210006, Jiangsu Province, China. cxf551101@sina.com
Telephone: +86-25-52887061
Fax: +86-25-52269924
Received: December 23, 2008
Revised: February 11, 2009
Accepted: February 18, 2009
Published online: May 21, 2009
Abstract

AIM: To investigate the clinicopathological roles of Bmi1 in esophageal squamous cell carcinoma (ESCC).

METHODS: Quantitative real-time polymerase chain reaction and immunohistochemical staining for Bmi1 were performed in cancerous and adjacent non-cancerous paraffin-embedded esophageal specimens.

RESULTS: The Bmi1 expression level was unaffected by gender and age. The level of Bmi1 mRNA in ESCC was significantly higher than that in the adjacent non-cancerous tissues (2.181 ± 2.158 vs 0.931 ± 0.894, P = 0.0152), and its over-expression was aggressively associated with lymph node metastasis (3.580 ± 2.487 vs 1.703 ± 0.758, P = 0.0003), poorer cell differentiation (P = 0.0000) and advanced pathological stage (3.827 ± 2.673 vs 1.590 ± 0.735, P = 0.0001). The patients were divided into high-expression and low-expression groups based on the median expression level of Bmi1 mRNA, and a shorter overall survival time in the former group was observed. Immunohistochemistry for Bmi1 oncoprotein showed diffusely positive, focally positive and negative expression in 44, 16 and 10 of 70 ESCC cases, respectively, compared with three, two and five of 10 adjacent non-cancerous cases (P = 0.027). The positive rate of the oncoprotein in samples of histological grade III was higher than that of grade II (P = 0.031), but its expression had no relation to the lymph node metastasis and pathological staging. In 70 ESCC samples, Bmi1 showed high intense expression in the cytoplasm and less or even no expression in the nucleus.

CONCLUSION: Bmi1 was over-expressed in ESCC. Increased Bmi1 mRNA expression was significantly associated with ESCC progression, and the oncoprotein was largely distributed in the cytoplasm of tumor cells.

Keywords: Esophageal squamous cell carcinoma; Bmi1; Quantitative real-time polymerase chain reaction; Immunohistochemistry; Clinicopathology