Expression and clinical significance of BUB1 in esophageal cancer.

OBJECTIVE: To investigate the expression levels, biological functions, and clinical significance of budding uninhibited by benzimidazoles 1 (BUB1) in esophageal squamous cell carcinoma (ESCC). METHODS: A total of 50 pairs of ESCC and adjacent normal tissues were collected for analysis. The human normal esophageal epithelial cell line (Het-1A) and the human esophageal cancer cell line (EC109) were cultured. Cells were transfected with pcDNA 3.1+BUB1 and shRNA-BUB1. The effects of BUB1 on cancer cells were assessed using CCK-8, Transwell migration and invasion assays, real-time quantitative PCR, and Western blot. Immunohistochemical staining was performed to analyze BUB1 expression in cancer tissues. Logistic regression analysis was used to evaluate the association between BUB1 expression and clinicopathological parameters. The predictive value of BUB1 expression for tumor differentiation, lymph node metastasis, and clinical stage was assessed using receiver operating characteristic (ROC) curve analysis. RESULTS: BUB1 was highly expressed in cancer tissues and cells. Overexpression of BUB1 promoted the proliferation, migration, and invasion of EC109 cells in vitro, while silencing BUB1 inhibited these processes (all P<0.05). The positive expression rate of BUB1 was higher in cancer tissues compared to normal tissues (70% vs. 30%, P<0.05). Logistic regression analysis revealed that BUB1 expression was significantly associated with tumor differentiation, lymph node metastasis, and clinical stage (all P<0.05). ROC curve analysis showed that the area under the curve (AUC) for BUB1 expression predicting tumor differentiation, lymph node metastasis, and clinical stage was 0.762, 0.789, and 0.831, respectively. CONCLUSION: BUB1 promotes the proliferation, migration, and invasion of esophageal cancer cells. Increased BUB1 expression is closely associated with tumor differentiation, lymph node metastasis, and clinical stage.