[Progression of leukoplakia is associated with changes in apoptotic and mitotic index as well as in p53 and Ki-67 expression].

INTRODUCTION

Leukoplakia is the most frequent preblastomatous alteration in the oral cavity. Its potential for malignant transformation is unpredictable. The aim of the present study was to provide data to the prognosis and molecular genetic background of this disease.

MATERIALS AND METHODS

Biopsy material from 15 leukoplakia patients and three oral squamous cell carcinoma patients treated at the Department of Periodontology, Semmelweis University were studied with histological and immunohistochemical methods. Hemotoxylin and eosin staining, Apop-Detect kit (for TUNEL reaction), immunohistochemical reactions for Ki-67 and p53 were applied. The severity of dysplasia, mitotic and apoptotic index and expression as well as distribution of Ki-67 and p53 were examined and related to the clinical appearance of leukoplakia.

RESULTS

Mitotic and apoptotic index, Ki-67 expression increased significantly in parallel with the severity of dysplasia and also with the clinical stage (homogenous, nodular erythroleukoplakia). Positivity and intracellular localisation of mutant p53 varied according to the clinical forms of leukoplakia. Homogenous and nodular forms showed cytoplasmic while erythroleukoplakia and carcinoma were characterized by nuclear positivity.

CONCLUSION

Increased mitotic, apoptotic and Ki-67 index may indicate unfavourable prognosis of leukoplakia. The expression of Ki-67 and p53 in various forms of leukoplakia varies in parallel with the severity of leukoplakia.