AIM:To determine the correlation between invasiveness,migration and prognosis in esophageal squamous cell carcinoma(ESCC)and expression of the B-cellspecific Moloney leukemia virus insert site 1(Bmi-1)and plasminogen activator inhibitor-1(PAI-1).METHODS:Eighty previously untreated patients who underwent surgical excision of ESCC were included.The expression of Bmi-1 and PAI-1 was examined immunohistochemically in formalin-fixed paraffinembedded primary tissue specimens.The relationships between the expression of Bmi-1 and PAI-1,the clinicopathologic features of ESCC,and the survival rate of ESCC patients were also discussed.The correlation between Bmi-1 and PAI-1 protein expression in ESCC was analyzed.The relationship between Bmi-1 and PAI-1expression and ESCC prognosis was evaluated using a Cox regression model and Kaplan-Meier survival curve analysis.RESULTS:The rates of positive Bmi-1 and PAI-1 expression in ESCC were higher than those in normal esophageal tissue(P<0.05).The expression of Bmi-1and PAI-1 was correlated with depth of invasion and lymph node metastasis(P<0.05),but not with patient age,tumor size or nationality(P>0.05).The expression of Bmi-1 was positively correlated with that of PAI-1(P<0.05).The 10-year overall survival rate for all patients was 20%(16∕80).Univariate KaplanMeier survival analysis showed that patients with high expression of esophageal PAI-1 and Bmi-1 had lower survival,however,the difference was not statistically significant.Cox multivariate analysis showed that PAI-1and Bmi-1 were not independent factors for survival rate,while the depth of tumor invasion and metastasis were independent factors affecting patient survival.CONCLUSION:The expression of Bmi-1 and PAI-1plays a role in ESCC progression,and may be used as a prognostic marker in ESCC. AIM: To determine the correlation between invasiveness, migration and prognosis in esophageal squamous cell carcinoma (ESCC) and expression of the B-cellspecific Moloney leukemia virus insert site 1 (Bmi-1) and plasminogen activator inhibitor-1 (PAI-1). METHODS: Eighty previously untreated patients who underwent surgical excision of ESCC were included. The expression of Bmi-1 and PAI-1 was examined immunohistochemically in formalin-fixed paraffinembedded primary tissue specimens. The relationships between the expression of Bmi-1 and PAI-I , the clinicopathologic features of ESCC, and the survival rate of ESCC patients were also discussed. correlation between Bmi-1 and PAI-1 protein expression in ESCC was analyzed. The relationship between Bmi-1 and PAI-1 expression and ESCC prognosis was evaluated as using a Cox regression model and Kaplan-Meier survival curve analysis .RESULTS: The rates of positive Bmi-1 and PAI-1 expression in ESCC were higher than those in normal esophageal tissue (P <0.05). The expres sion of Bmi-1 and PAI-1 was correlated with depth of invasion and lymph node metastasis (P <0.05), but not with patient age, tumor size or nationality (P> 0.05). The expression of Bmi-1 was positively correlated with that of PAI-1 (P <0.05) .The 10-year overall survival rate for all patients was 20% (16/80) .Univariate KaplanMeier survival analysis showed that patients with high expression of esophageal PAI-1 and Bmi-1 had lower survival, however, the difference was not significant significant. Cox multivariate analysis showed that PAI-1 and Bmi-1 were not independent factors for survival rate, while the depth of tumor invasion and metastasis were independent factors affecting patient survival. CONCLUSION: The expression of Bmi-1 and PAI-1plays a role in ESCC progression, and may be used as a prognostic marker in ESCC.