RESUMO
Oral Squamous Cell Carcinoma [OSCC] is usually preceded by precancerous lesions. These lesions appear white or red clinically [Leukoplakia and Erythroplakia respectively] and show dysplastic epithelial changes on histopathological examination [Abbas et al, 2007]. If p53 alterations [gene mutations and protein expression] in premalignant lesions are detected and treated in their early stages, it might help in prevention of progression to cancer [Patton et al, 2008]. Aim was to determine the frequency of p53 gene mutation and protein expression in oral epithelial dysplastic lesions. This was a descriptive study carried out at the Armed Forces Institute of Pathology [AFIP], Rawalpindi and was of one year duration from 8[th] May 2010- 5[th] May 2011. Thirty cases of oral epithelial dysplasia [OED] were retrieved from the record files. Some fresh /frozen sections were also included. Gene p53 mutation was detected in these cases by PCR-SSCP Analysis. DNA was extracted from the formalin-fixed and paraffin-embedded tissue sections and fresh /frozen sections. DNA thus extracted was amplified by polymerase chain reaction. The amplified products were denatured and finally analyzed by gel electrophoresis. Gene mutation was detected as electrophoretic mobility shift. The immunohistochemical marker p53 was applied to the same 30 cases andproteinp53 expression was recorded. Mutations of the p53 gene were detected in 20% of the dysplastic lesions. Immunohistochemical staining ofmarkerp53 was positive in 60% of the cases. Gene p53 mutation and protein expression was not coexistent