Pilot Study: DP, PKP-1 Expression in Oral Epithelium

Oral cancer affects 3% of the United States population, and the prognosis has not improved today even with new treatment protocols. Oral cancer may be preceded by premalignant disease that appears histologically as dysplasia. Diagnosing dysplasia is subjective and depends upon the training and experience of the oral pathologist. Identification of molecular markers for cellular change would assist in determining the risk of dysplasia progressing to oral squamous cell carcinoma (OSCC). It seems likely that earlier diagnosis should improve the prognosis of oral cancer. Objective: In the present study, we sought to determine if altered desmosomal cell-cell adhesion correlates with histological diagnosis of dysplasia and OSCC. Methods: Using paraffin-embedded formalin fixed human tissues, we performed IHC using antibodies specific for desmoplakin and plakophilin-1. We compared staining in normal oral mucosa, dysplastic, and OSCC tissues obtained from the UNMC College of Dentistry Oral Biopsy Service. Results: Our results showed that dysplastic tissue samples showed decreased expression of both membrane DP and pkp-1 proteins as compared to the protein expression in normal oral epithelium. Furthermore, the protein expression was lower in OSCC as compared to dysplastic tissue. There was a greater decrease in protein expression between normal and dysplastic tissue than dysplastic and OSCC. In addition, we compared same subject cases that displayed OSCC that were previously diagnosed as dysplastic. Conclusion: Our findings suggest that expression of plakophilin-1 and desmoplakin may be helpful in identifying dysplasias which may progress to OSCC. This study was funded by the UNMC College of Dentistry Summer Research Fellowship 2007.