The prognostic significance assessment of Ki-67, MCM-2 and p53 proliferation markers in dysplasia and oral squamous cell carcinoma.

Tumor markers are the precursor molecules in clinical assessment of diseases and determination of the prognosis, thus achieving to conceive the accurate tumor biology. This study is planned in the purpose of investigating the prognostic significance of Ki-67, MCM-2 and p53 proliferation markers in oral dysplastic lesions and oral squamous cell carcinomas with healthy oral mucosa. The study is performed by 50 specimens taken from 47 patients. The control group was formed from 10 healthy normal oral mucosa taken from the impacted third molar surgery operation of 7 patients (4 females, 3 males) between the ages 21-69 (30,28±17,26). The study group was formed from 40 specimens of dysplasia and oral squamous cell carcinoma taken from 40 patients (17 females, 23 males) between the ages 32-79 (62,02±12,74). Ages and genders of the patients, localizations of tissue samples, clinical and histopathological diagnosis, grades of dysplastic lesions and tumors, expressions of Ki-67, MCM-2 and p53 on sections were recorded. p53 expression of oral squamous cell carcinoma (OSCC) localized at mandible (48,92±25,63) was statistically higher than the expression at maxilla (24±16,22), p<0.05. Ki-67, MCM-2 and p53 expressions in OSCC were significantly higher than the expressions in controls (p<0.001) and dysplasias (p<0.05). Ki-67 expression in mild dysplasia (13,8±5,6) was statistically lower than the expression in moderate dysplasia (19,83±6,91), p=0,047. There was no statistical difference between the expressions of MCM-2 (p=0,94) and p53 (p=0,54) in both grades of dysplasia. There was also no significant difference between the mean expressions of Ki-67 (37,35±16,43, 39,5±24,47) and MCM-2 (28,13±10,3, 36±20,21) in well and moderately differentiated OSCC. p53 expression in well differentiated OSCC (33,17±20,98) was statistically lower than its expression in moderately differentiated OSCC(53±25,99), p=0,037. A positive correlation was found between the mean expressions of Ki-67 with MCM-2 and MCM-2 with p53 in OSCC. Ambiguity of methods in accurate discrimination between the grades of dysplastic lesions still persists in the expressions of proliferation markers used in this study. We conclude that; Ki-67 expressions reveal more significant outcomes when compared with MCM-2 and p53 expressions. Furthermore, we suggest that Ki-67 marker is more reliable in distinguishing the grades of dysplasia than the others we examined.Keywords: dysplasia; oral squamous cell carcinoma; Ki-67; MCM-2; p53