Morphologic Evaluation of P53 Apoptotic Signaling Responses and Proliferative Activity of Ki-67 in Oral Lichen Planus, Oral Squamous Cell Carcinoma and Normal Specimens

Oral lichen planus is not a rare condition in human being. This inflammatory disease is generally regarded as a benign pathology; however, transformation toward malignant conditions in some cases has forced many physicians to consider lichen planus as a premalignant entity. This study investigates and compares the rate of Ki-67 and P53 expression in patients with oral lichen planus and oral Squamous Cell Carcinoma (SCC) in comparison with normal subjects. In this prospective study, paraffin-embedded specimens of histopathologically proved oral lichen planus (n = 30), oral SCC (n = 20) and oral buccal mucosa of normal subjects (n = 20) were examined at Tabriz Imam Reza Hospital within a one-year period of time. Monoclonal antibodies against Ki-67 and P53 were used for determining the rate of expression of these two markers. The three groups were matched for patients’ age and gender. Ki-67 was expressed in 26 patients (86.7%) in lichen planus group, in 20 patients (100%) in SCC group and in 4 normal subjects (20%). The rate of Ki-67 positivity was significantly higher in lichen planus and SCC groups than in normal subjects (p<0.001). P53 was positive in 26 patients (86.7%) in lichen planus group, in 20 patients (100%) in SCC group and in 8 normal subjects (40%). The rate of P53 positivity was significantly higher in lichen planus and SCC groups than in normal subjects (p<0.001). In conclusion, this study confirmed that lichen planus could be regarded as a potentially premalignant condition.