Immunohistochemical Expression of DAPK-1 in Oral Leukoplakia And Oral Squamous Cell Carcinoma: A Preliminary Study

DAPK-1 IHC expression was increased in OLs without dysplasia and with OLs with mild dysplasia compared to moderate/severe dysplasia (p=0.019, Mann-Whitney U Test) and OSCCs (p=0.003, Mann-Whitney U Test). Conclusions: DAPK-1 seemed to function as an oncosuppressor molecular biomarker, as its expression was decreased in areas of cellular dysplasia in OLs and in areas of OSCCs composed of less differentiated cells. The clinical application of this biomarker is that the positively stained, potentially malignant lesions are less likely to transition into malignancy, and cancerous lesions are more likely to behave non-aggressively. On the other hand, the lack of staining could signify the loss of this oncosuppressing ability, and it could be a potential prognostic biomarker for OSCC's aggressive biologic behavior if considered with other clinical parameters and a prognostic factor of malignant transformation of potentially malignant lesions. Since this is a preliminary study, more studies with larger sample sizes are required to support these conclusions.