Expression of Proliferating Cell Nuclear Antigen (PCNA) in Oral Submucous Fibrosis: An Immunohistochemical Study.

Abstract

Expression of Proliferating Cell Nuclear Antigen (PCNA) well-correlates with the cell division. The suprabasal expression of PCNA is considered to be a marker of dysplastic oral mucosa indicating a special proliferative cellular state in those lesions. Oral submucous fibrosis (OSMF) is considered to be a premalignant condition with potential to get transformed into oral squamous cell carcinoma (OSCC). The present study was done to assess the PCNA expression in different grades and in different layers of epithelium of OSMF and to compare the expression of PCNA in OSMF with OSCC. A group of 40 histopathologically diagnosed, formalin fixed, paraffin embedded tissue samples were included in study. The study group was further divided into 2 groups; 30 OSMF and 10 OSCC. Theses samples were collected from Department of Oral and Maxillofacial Pathology, Government Dental College and Research Institute, Bangalore. The samples were subjected to immunohistochemical method using indirect immunoenzyme LSAB method. All 40 cases showed positivity for PCNA. The percentage of positive cells was more in basal and suprabasal layer both in OSMF and OSCC, whereas the greater percentage of positive cells was seen in the superficial layer of OSCC. All OSMF cases showed positive expression in basal and suprabasal layer and only 77% of cases showed positive PCNA expression in the superficial layer with variable immunoreactivity and 23% did not show any positive staining in the superficial layer. The percentage of positive cells and the intensity of staining increased as the disease severity increased in OSMF. Increased proportion of cells expressed PCNA staining which are in proliferative layers of OSMF. This biomarker provides an insight into the biological behaviour of the condition that substantiates its potentially malignant nature and may also provide an intermediate end point in chemotherapeutic trials.