The role of apoptosis and bcl-2 protein in topical treatment of oral leukoplakia with isotretinoin.

BACKGROUND: This study evaluates the role of bcl-2 protein, as well as, of apoptotic bodies in the topical treatment of oral leucoplakia with 13-cis-retinoic acid (isotretinoin). To test this role, a clinical, histological and immunohistochemical study of the treated lesions was carried out, so as to verify the role of apoptosis and its genetic control mechanism of the development, progression and therapy of preneoplastic lesions. METHODS: A Double-blind study was carried out on 15 patients afflicted with oral leukoplakia. They were treated daily (3 topical applications) with 0.1% isotretinoin gel or a placebo for 4 months. Afterwards, the patients treated with placebo were administered the active medication for an additional 4 month period. RESULTS: All the patients, with the exception of one patient who was lost to follow-up, who finished the treatment, showed a marked improvement of the dimension and the clinical aspect of the lesions (3 total remission, 11 improvement of the size and clinical appearance of the lesion of 50% or more). The immunohistochemical analysis for bcl-2 protein showed a weak positive reaction of the level in the basal membrane of the specimens collected before the pharmacological treatment; after the pharmacological treatment almost all the specimens with the exception of one, tested completely negative for bcl-2 protein. In the specimens collected before the pharmacological treatment only a few apoptotic bodies were observed, while after treatment the samples showed a noticeable increase of apoptotic bodies. CONCLUSIONS: A statistical analysis showed that the difference in the positive reaction to bcl-2 protein between the 2 groups is not statistically significant (p = 0.132). On the other hand, the difference in the count of apoptotic bodies between the 2 groups is statistically significant (p = 0.0193)