association between bmi1 and clinicopathological status of esophageal squamous cell carcinoma aim to investigate the clinicopathological roles of bmi1 in esophageal squamous cell carcinoma esccmethods quantitative realtime polymerase chain reaction and immunohistochemical staining for bmi1 were performed in cancerous and adjacent noncancerous paraffinembedded esophageal specimensresults 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 noncancerous tissues 2181 2158 vs 0931 0894 p 00152 and its overexpression was aggressively associated with lymph node metastasis 3580 2487 vs 1703 0758 p 00003 poorer cell differentiation p 00000 and advanced pathological stage 3827 2673 vs 1590 0735 p 00001 the patients were divided into highexpression and lowexpression 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 noncancerous cases p 0027 the positive rate of the oncoprotein in samples of histological grade iii was higher than that of grade ii p 0031 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 nucleusconclusion bmi1 was overexpressed in escc increased bmi1 mrna expression was significantly associated with escc progression and the oncoprotein was largely distributed in the cytoplasm of tumor cells