p53 immunoprofiling of potentially malignant oral disorders: a case series analysis

p53 tumor suppressor gene which is a frequent target for mutations in a high percentage of oral cancer is regarded as an early event in carcinogenesis.

The role of p53 was assessed in potentially malignant oral disorders (PMOD) to ascertain its prognostic significance.

Retrospective case series analysis was carried out on 30 paraffin-embedded tissue blocks of confirmed oral leukoplakia with dysplasia.

10 cases of each of mild, moderate, and severe dysplasia were immunohistochemically analyzed for p53 expression. The intensity of staining, intracellular localization, and basal and/or suprabasal distribution were assessed.

The intensity of p53 staining and its distribution were analyzed by the Chi-square test. The intracellular localization of p53 in different grades of dysplasia was subjected to one way ANOVA. P<0.05 was considered significant.

21/30 cases of epithelial dysplasia were positive for p53 immunopositivity. Intensity of p53 expression was strong in 12 cases and weak in 9 cases (P<0.05). p53 positivity was confined to basal cells in mild dysplasia, while severe dysplasia showed both basal and suprabasal staining (P<0.05). Nuclear and cytoplasmic staining between and within the groups were F=9.027 and F=6.465 respectively with high significance noted between mild dysplasia and severe dysplasia.

Increased p53 expressivity and greater cellular localization with increase in the severity of dysplasia indicated a direct association between the degree of epithelial dysplasia and p53 accretion, which occurs as an early event in oral carcinogenesis.