Minichromosome maintenance-2 (MCM2) expression differentiates oral squamous cell carcinoma from pre-cancerous lesions.

Proteins necessary for DNA replication and normal regulation for the cell cycle include minichromosome maintenance-2 (Mcm-2). Overexpression of this protein in several premalignant and malignant lesions has been observed. In this study, the diagnostic value of Mcm-2 expression in distinguishing histologically-proven normal oral mucosa (NOM), oral benign keratosis (OBK), oral epithelial dysplasia (OED), and oral squamous cell carcinoma (OSCC) was investigated. In this descriptive analytical study, 73 archived specimens of oral tissues, including 20 OBK, 20 OED, 20 OSCC, and 13 NOM cases were selected. The means of labeling indices (LIs) of Mcm-2 expression by immunohistochemistry in each category of lesions were calculated. The data was analyzed by one-way ANOVA, discriminant analysis, and Fisher's exact tests. The means of labeling indices (LIs) of Mcm-2 expression show statistically significant difference between the four studied groups (P<0.001). Mcm-2 had overexpression and higher positivity in OSCCs. A cut-off point of 67% was determined in order to distinguish OSCC from precancerous lesions. The findings indicated that Mcm-2 could be a useful marker for early detection of oral SCC and dysplasia. Also, due to the overexpression of this marker in OSCC, there exists the possibility of application of Mcm-2 for molecular target therapy in these patients.