DOWN-EXPRESSION OF TETRASPANIN CD9 IS A SENSITIVE MARKER FOR IDENTIFYING PRE-MALIGNANT CHANGES IN THE ORAL EPITHELIUM

Objectives Tetraspanins, cell surface proteins that mediate cell-cell and cell-extracellular matrix interactions, are capable to modify cell motility, thus being potential diagnostic markers in pre-malignant conditions. We examined the immunohistochemical expression of tetraspanins CD9, CD81 and CD63 in normal oral mucosa as well as in inflamed, dysplastic and neoplastic epithelial lesions. Findings Included were cases of normal oral mucosa (NOR, N=15), oral lichen planus (OLP, N=51), hyperkeratosismild dysplasia (HK, N=29), moderate-severe dysplasia (DYSP, N=22), oral squamous cell carcinoma (OSCC, N=31), and normal-looking mucosa nearby OSCC (N-OSCC, N=18). Staining, assessed as percent of stained cells multiplied by staining intensity (1=weak, 2=strong), was evaluated per epithelial thirds (basal, middle and upper) and then as total staining score (sum of all thirds). Statistical analysis was performed using One-way ANOVA. Receiver operating characteristic (ROC) curve was used for diagnostic sensitivity. Statistical significance was set at P Conclusions CD9 could accurately discriminate between normal (high expression) and all other types of pathologies (lower expression) with high diagnostic sensitivity. In addition, expression of CD9 in neoplasia and the nearby histologically “normal-looking” epithelium was similar but significantly lower than in dysplasia and OLP. Therefore, the expression of CD9 could aid in defining the nature of equivocal histopathological changes in oral epithelial lesions.