Differences in the expression of p53 protein in oral lichen planus based on the use of monoclonal antibodies DO7 and pAb 240 M.A. Gonzalez-Moles a, * , J.A. Gil-Montoya a , I. Ruiz-Avila b , F. Esteban c , A. Bascones-Martinez d a Oral Medicine, Dental School, Granada University, Spain b Pathology Department, Jaen General Hospital, Spain c ENT Department, Virgen del Rocı ´o University Hospital, Sevilla, Spain d Periodontology Department, Dental School, Complutense University, Madrid, Spain Received 6 June 2007; received in revised form 22 June 2007; accepted 23 June 2007 KEYWORDS Oral lichen planus; p53; Malignant transformation Summary A comparison is made of p53 expression in oral lichen planus, detected via mono- clonal antibodies pAb240 and DO7, and with cell apoptosis and proliferation markers. An immu- nohistochemical 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 signif- icant 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. ª 2007 Elsevier Ltd. All rights reserved. Introduction Oral lichen planus (OLP) is a chronic, relapsing inflammatory disease involving T lymphocyte aggression targeted to the basal layer of the oral mucosa. 1,2 Although the subject is controversial, 3 some authors 4,5 consider that OLP should be regarded as a precancerous lesion, with a malignant transformation rate of 0.5–2%. 6 In this context, patients who have developed a first carcinoma tend to suffer multi- ple tumors – this leading to field malignization phenom- ena. 4,5,7,8 Studies of the malignant transformation of OLP indicate that there are no factors clearly associated with 1368-8375/$ - see front matter ª 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.oraloncology.2007.06.013 * Corresponding author. Present address: Facultad de Odonto- logı ´a, Paseo de Cartuja s/n, 18071 - Granada (Spain). Tel.: +34 958243804; fax: +34 958240908. E-mail address: magonzal@ugr.es (M.A. Gonzalez-Moles). Oral Oncology (2007) xxx, xxx– xxx available at www.sciencedirect.com journal homepage: http://intl.elsevierhealth.com/journals/oron/ ARTICLE IN PRESS Please cite this article in press as: Gonzalez-Moles MA et al., Differences in the expression of p53 protein in ......, Oral Oncol (2007), doi:10.1016/j.oraloncology.2007.06.013