Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 8 2 2016 03 01 Immunohistochemical Evaluation of Ki-67 Expression in Erosive andNon-Erosive Oral Lichen Planus 1 1 10.17795/ajdr-25372 EN Narges Gholizadeh Masoumeh Mehdipour Esmaiil Dadgar Ayla Bahramian Delaram Ebrahimpour Moghaddas Journal Article 10.17795/ajdr-25372 2014 11 15 2015 05 20 Background: Oral lichen planus (OLP) is a relatively common, chronic inflammatory condition, which is considered a precancerous lesion. The Ki-67 antigen is expressed in all the phases of the cellular cycle in proliferative cells. Different studies have suggested the relationship between incidences of malignancy in precancerous lesions and the occurrence of this protein. Objectives: This study aimed to evaluate Ki-67 expression in erosive and non-erosive oral lichen planus. Materials and Methods: Specimens (formalin-fixed and paraffin-embedded) of 30 lesions of erosive OLP and 30 lesions of nonerosive OLP were referred for immunehistochemistry (IHC) analysis of Ki-67. Results of immunohistochemistry were statistically evaluated by means of the chi-square test and independent t-test. The level of statistical significance was established at P < 0.05. Results: The mean expression of Ki-67 in patients with erosive OLP was higher than people in the control group. These differences were statistically significant (P = 0.041). Conclusions: Since Ki-67 is extensively accepted as an important biomarker in diagnosis, prognosis and treatment of cancerous and precancerous lesions, a high degree of presence of this biomarker in chronic precancerous lesions, such as erosive OLP, can be of great use in prognosis and suggested treatments.