Seoul, Republic of Korea – At the 94th General Session & Exhibition of the International Association for Dental Research, researcher Jonas Sundberg, University of Gothenburg, Sweden, presented a study titled “Increased Expression of p16 in Oral Leukoplakia the Last Decade.”
During the last two decades an increase in incidence of oropharyngeal carcinomas related to human papilloma virus (HPV) infection has been reported. Although a casual association between lekoplakia, oral cancer, and HPV has been suggested in several reports, no conclusive evidence has been presented. To assess the presence of HPV, the tumor suppressing protein p16 is commonly used as a surrogate marker for HPV infection. The aim of the present study is to investigate whether p16 expression in tissue specimens from lekoplakia has increased during the last decade, which may indicate an increase in incidence of oral HPV infection.
A patient cohort with tissue specimens obtained between 1992 and 2001 and a cohort where specimens were obtained between 2011 and 2015 and with histopathological diagnoses of benign hyperkeratosis or hyperkeratosis with dysplasia were examined. Immunohistochemistry was performed using a monoclonal antibody (clone E6H4; Roche Ltd) visualizing p16. Digitalized images of sections were obtained and a semiquantitative scale (0-5) was used to enumarate p16 expression in oral epithelium.
In the 2011-2015 cohort lekoplakia epithelium showed a significant increase (P = .02) in grade 4 and 5 p16 expression in comparison with lekoplakia epithelium in the 1992-2001 cohort. In lekoplakia presenting with dysplasia, grade 4 and 5 p16 expression also increased significantly (P = .0001) over time when comparing the cohorts. The results indicate an increase in HPV infection in lekoplakia during the last decade. Researchers are further investigating the presence of HPV DNA utilizing polymerase chain reaction is presently undertaken.
This research was funded by the Regional Research Council, Region Västra Götaland, Assar Gabrielsson Foundation and the Swedish Dental Society.