Prognostic implications of CD44, NANOG, OCT4, and BMI1 expression in tongue squamous cell carcinoma

Background Tongue squamous cell carcinoma (SCC) contains a cell subpopulation referred to as cancer stem cells (CSCs), which are responsible for tumor growth, metastasis, and resistance to chemotherapy and radiotherapy. The CSC markers have been used to isolate these cells and as biomarkers to predict overall survival. Methods The CSC markers CD44, NANOG, OCT4, and BMI1 were investigated using reverse transcriptase‐quantitative polymerase chain reaction (RT‐qPCR) and immunohistochemistry and correlated with clinicopathological parameters. Results The CD44 overexpression was associated with disease‐related death (P = 0.02) and worst prognosis. NANOG was upregulated in nontumoral margins and associated with T1/T2 classification, lymph node metastasis, and worst prognosis. OCT4 was associated with lymph node metastasis and worst overall survival. BMI1 and CD44v3 were overexpressed in tongue SCC. Coexpression of CD44++/NANOG++ was associated with worst overall survival when compared with patients with CD44‐/+/NANOG‐/+. Conclusion The CSC markers might play an important role not only in CSC trait acquisition but also in tongue SCC development and progression.