Expression And Clinical Significance Of Bub1mRNA And Protein, Mad2 Protein In Esophageal Cancer

Background and objective Esophageal cancer is one of the most common malignant cancers in the world, and there has a high incidence rate in our country. In the past century, people have devoted themselves to the worldwide problem——cancer, which does harm to people's health. Of late years, much research has been found that spindle checkpoint, which is a highly conservative mitotic watch system in the kinetochore of chromosome, has close correlations with chromosome instability and tumorigenesis. So we will study the relationship between Bub1, Mad2, which are important components of spindle checkpoint, and esophageal cancer. We have two objectives. First is to investigate the expression of Bub1 mRNA and protein, Mad2 protein in esophageal cancer and their relationship with clinical pathological parameters. Second is to explore the role of Bub1 and Mad2 in carcinogenesis and progression of esopageal cancer and to evaluate their clinicopathologic significances.Methods Esophageal cancer tissues and their corresponding normal esophageal musocas were collected for immunohistochemical staining, in situ hybridization and western blot analysis. The study was emphasized on the expression of Bub1 mRNA, Bub1 protein and Mad2 protein between esophageal cancer and normal esophageal musoca.Results 1. The expression of Bub1 mRNA and Bub1 protein were significantly decreased in esophageal cancer ( P<0.005 ). The expression of Bub1 mRNA and Bub1 protein in esophageal cancer was obviously related with degree of differentiation and lymph node metastasis ( P<0.05 ). A positive correlation was found between the expression of Bub1 protein and Bub1 mRNA ( r = 0.558,P<0.05 ). 2. The expression of Mad2 protein was significantly reduced in esophageal cancer ( P<0.05 ), and was obviously related with degree of esophageal cancer differentiation ( P<0.05 ). 3. A positive correlation was found between the expression of Bub1 protein and Mad2 protein ( r = 0.413,P<0.05 ).Conclusion 1. Close relation is found between the carcinogenesis of esophageal cancer and the reduced expression of Bub1 mRNA, Bub1 protein and Mad2 protein. Low expression of Bub1 also plays an important role in progression and metastasis of esophageal cancer. 2. Bub1 protein expression is regulated mainly at the transcriptional level. The reduction of Bub1 protein expression is correspondingly the result of reduction of transcriptional level. 3. Bub1 protein cooperates with Mad2 protein during the carcinogenesis of esophageal cancer. 4. It might be much more significant and a new treatment approach to investigate the expression of Bub1 and Mad2 protein combinedly in esophageal cancer than to investigate the expression of only one of them.