Purpose: This study was conducted to evaluate the usefulness of minichromosome maintenance 3 (MCM3) as a biomarker for diagnosis of oral premalignant lesions and SCC. 

  Materials and Method: In this study, 31 oral SCC, 20 dysplastic epithelium and 20 controls were selected and immunohistochemical staining was done for MCM3. ANOVA, Tukey HSD, Mann-Whitney and Kruskal-Wallis tests were used to compare the groups and the correlation between different grades.

Results: There was increasing trend of MCM3 from control to dysplastic epithelium and from dysplastic epithelium to SCC both in suprabasal layers and in total epithelial layers. MCM3 expression was elevated with increasing the grade of dysplasia, but there was no statistically significant difference (p= 0.93). The expression was also increased in high grades of SCC compared to lower grades. 

  Conclusion: MCM3 can be used as a useful biomarker in the diagnosis of premalignant lesions and oral SCC.