BACKGROUND: Tumor budding is a readily detectable histopathological feature and has been recognized as an adverse prognostic factor in several human cancers. However, the prognostic value of tumor budding in tongue squamous cell carcinoma (TSCC) has not been reported. The purpose of this study was to assess the correlation of tumor budding with the clinicopathologic features, and the known molecular biomarkers (E-cadherin and Vimentin), as well as to evaluate its prognostic significance for TSCC. METHODS: Archival clinical samples of 230 patients with TSCC were examined for tumor budding. Immunohistochemistry analyses were performed to examine the expression of E-cadherin and Vimentin. Statistical analyses were carried out to assess the correlation of tumor budding with clinicopathologic parameters and patient survival. The potential association between tumor budding and alterations of E-cadherin and Vimentin expression was also assessed. RESULTS: Of the 230 TSCC cases examined, tumor budding was observed in 165 cases (71.7%), with a mean tumor bud count of 7.5 (range from 1 to 48 buds). High-intensity budding (≥5 tumor buds) was observed in 111 cases (48.3%). Statistical analysis revealed that tumor budding was associated with tumor size (P < 0.05), differentiation (P < 0.05), clinical stage (P < 0.05), lymph node metastasis (P < 0.01), and correlated with reduced overall survival. In addition, significant associations were observed among tumor budding and the deregulation of E-cadherin (P < 0.001) and Vimentin (P < 0.001). CONCLUSIONS: Tumor budding, which associates with epithelial-mesenchymal transition, is a frequent event and appears to be an independent prognostic factor in TSCC.