"Estudo da expressão da p16 em casos de líquen plano bucal"
We realized immunohistochemical procedures with p16 and Ki-67 in lesions of oral lichen planus to verify the presence and kind of its immunoexpression amog the two groups of patients, asymptomatic and symptomatic, correlating the clinical and histopathological diagnosis with the immunohistochemical data in order to verify if oral lichen planus can be considered a lesion with risk of malignant transformation. MATERIAL AND METHOD: nine asymptomatic patients and 12 symptomatic of oral lichen
... f oral lichen planus. Five cases of inflammattory fibrous hyperplasia were included as control group. For immunohistochemical studies we used p16 (prediluted-BioSB/USA) and Ki-67 (clone MIB-1-DAKO/USA) by Envision Labelled techniques (DAKO). Results were annalyzed according to parameters based on Klaes et al. (2001) evaluating the immunomarked cell rates, the distribution through the epithelial layer and the immunoexpression intensity. The statistics analysis proceeded the study of relative risk between asymptomatic and symptomatic patients regarding to its cellular immunoexpression (nuclear, cytoplasmic or both), the more prevalent topography of the lesion (buccal mucosa and tongue) and clinical characteristics (atrophic and reticular types). RESULTS: the correlation between asymptomatic and symptomatic patients was statistically significant (p<0.05) when comparison was made of the distribution of p16 throug the epithelial layer by analysis its cellular imumunoexpression. The nuclear immunoexpression of p16 showed an odds ratio of 4.091. The nuclear and cytoplasmatic were 5.179. The odds ratio for cytoplasmatic expression was 8.461. The correlation between immunoexpression and topography resulted in an odds ratio of 5.130 for tongue and 14.234 for buccal mucosa. The other categories availed as percentage and intensity of the p16 immunoexpression, clinical characteristics, besides the Ki-67 results gave non significant results. CONCLUSIONS: The citoplasmatic expression results indicates that this immunoexpression must not be discarded, as suggested by some studies. The high relative risk saw in buccal mucosa rather than tongue was an unexpected result, because the localization pointed as with greater involvement in cases of malignat transformation is the tongue. The distribution was the only one that reached a statistically significant result, so further studies must be made in order to include or exclude the human papillomavirus presence in oral lichen planus lesions, since the p16 protein is currently nowadays used as an indicator of cellular abnormalities in cervical lesions, where its overexpression is related to the presence of high risk human papillomavirus, beyond study of p16 in the cases of liquenoid dysplasia.