Differences in the expression of p53 protein in oral lichen planus based on the use of monoclonal antibodies DO7 and pAb 240

Summary A comparison is made of p53 expression in oral lichen planus, detected via monoclonal antibodies pAb240 and DO7, and with cell apoptosis and proliferation markers. An immunohistochemical study was made of 51 cases of oral lichen planus and 26 controls, using monoclonal antibodies DO7 and pAb240, anti-caspase-3 antibody and Mib-1 antibody against Ki-67. The cases showed important p53 expression with D07 (68%, 36 cases), presumably wild p53, and low p53 expression with pAb240 (14.9%, 7 cases), presumably mutated p53. No significant relationship was observed between p53 expression and caspase-3 apoptosis marker, though an association was recorded between p53 expression with DO7 and Ki-67 expression. Conclusions: In oral lichen planus, p53 protein preferentially activates the cell cycle for DNA repair, this representing a very effective genome vigilance mechanism, in view of the low rate of malignant transformations observed in this disease.