EPITHELIAL MESENCHYMAL TRANSITION AND CANCER STEM CELL MARKERS IN ORAL EPITHELIAL DYSPLASIA AND ORAL SQUAMOUS CELL CARCINOMA

The role of cancer stem cells (CSC) in oral cancer is widely accepted. Yet, the existence of CSC in dysplastic tissue and the molecular pathways of progression from dysplasia to malignancy remain to be explored. Our retrospective study aimed to analyze the presence of CSC in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC) concerning two epithelial-mesenchymal transition markers: Snail and E-cadherin. Formalin-fixed, paraffin-embedded tissue samples of oral epithelial dysplasia (OED), OSCC, and oral epithelial hyperplasia (OEH) were used. Immunohistochemistry and quantitative RT-qPCR detected the expression of Snail and CD133, whereas CD44 and E-cadherin were evaluated solely immunohistochemically. OSCC cases showed significantly higher CD133 immunoreactivity and inflammation scores and significantly decreased E-cadherin expression compared to OED and OEH groups. Snail mRNA up-regulation was seen in 100% of the OSCC cases followed by 85% for OED cases and 82.5% OEH cases among those that displayed positive mRNA expression by RT-qPCR. The Snail upregulation in all OSCC cases proves that Snail plays a significant role in oral cancer. Our results also suggest that CD133 and E-cadherin may be potential diagnostic markers in oral cancer progression.