Novel role of microtubule-associated serine/threonine kinase like (MASTL) as a good prognostic factor in oral squamous cell carcinoma and evidences for a link with Smad7

Introduction: Upregulated microtubule-associated serine/threonine kinase like (MASTL), a cell cycle kinase required for a progression through mitosis, expression has been associated to poor prognosis. This study is aimed to investigate the clinical relevance of MASTL expression in oral squamous cell carcinoma (OSCC), and a possible mechanistic link with epithelial-mesenchymal transition (EMT). Methods: Immunohistochemical analysis of MASTL, E-cadherin, Vimentin, and Smad7 was performed in paraffin-embedded tissue specimens from 148 OSCC patients. Results: Nuclear MASTL expression was detected in 115 (77.7%) OSCC specimens. High MASTL expression was significantly associated with the male gender, smoking habit, T stage, early clinical stage, and absence of vascular invasion. MASTL expression was inversely correlated with Smad7, whereas no association was observed with E-cadherin and Vimentin. Patients harboring tumors with low MASTL expression exhibited a poorer overall survival. Smad7 expression was significantly related to reduced disease-specific and overall survival. High levels of MASTL expression were associated with better prognosis in T3 patients, N0 cases, and patients treated by surgery combined with radiotherapy and chemotherapy. Conclusion: The present study uncovers MASTL as a good prognostic factor in OSCC, and a potential link with EMT via Smad7.