Role of FBXW7 in esophageal squamous cell carcinoma: a potential biomarker for tumor progression and prognosis

Background: The role of F-box and WD repeat domain-containing protein 7 (FBXW7) in cancer remains controversial, as it has been reported to function as either a tumor suppressor or an oncogene depending on tumor type. This study was designed to investigate the role of FBXW7 in esophageal squamous cell carcinoma (ESCC). Methods: FBXW7 protein expression was examined by immunohistochemistry in ESCC tissues and matched adjacent nontumor tissues from 69 ESCC patients. The functional effects of FBXW7 were evaluated in two ESCC cell lines (Eca109 and EC9706) using FBXW7 overexpression and knockdown models to assess cell migration and invasion in vitro. In addition, a tumor-bearing mouse model was established to evaluate the effects of FBXW7 overexpression and knockdown on ESCC tumorigenesis and progression in vivo. Results: FBXW7 protein was significantly upregulated in ESCC tissues compared to adjacent nontumor tissues. FBXW7 upregulation was significantly associated with poor differentiation, deeper tumor invasion, and the presence of lymph node metastasis. FBXW7 overexpression could promote the migration and invasion of Eca109 and EC9706 cells in vitro, as well as enhance the proliferation and tumorigenicity of ESCC cells in vivo. Its knockdown significantly inhibited cell migration, invasion, and proliferation in vitro and reduced tumor growth in vivo. Conclusions: FBXW7 showed a tumor-promoting effect on ESCC, which may be a biomarker for the diagnosis and treatment of ESCC.