bcl-2 expression and apoptotic bodies in 13-cis-retinoic acid (isotretinoin)-topically treated oral leukoplakia: a pilot study

Tn a double-blind study 10 patients with oral leukoplakia were treated dail y (three topical applications) with 0.1% isotretinoin gel or a placebo for 4 months. Nine patients completed the treatment, while one patient was lost to follow-up. Subsequently, the patients who had received the placebo used the active medication for an additional 4 months. All patients treated wit h the active medication showed a significant improvement of the oral lesion s while, in the patients receiving only the placebo, the size of the lesion s remained the same. Also the group of patients who received the active med ication after the placebo showed an improvement in the size and clinical ap pearance of the lesions. A complete response was defined as the complete di sappearance of the lesion as assessed by visual inspection, while a partial response was defined as a 50% or more reduction in the size of the lesions . In total we had a complete response and eight partial responses. No side- effects from the use of the gel were ever observed. The percentage of bcl-2 -positive cells was evaluated in the basal layer from a minimum of 1000 cel ls in each case and the bcl-2 immunostaining was scored using three groups: - (less than or equal to 10% cells); + (less than or equal to 50% cells); + + (greater than or equal to 50% cells). The presence of apoptotic bodies was evaluated in a random fashion in the parabasal layer in 20 HPF. Immunoh istochemical analysis for bcl-2 protein showed that before treatment a weak positivity of the basal layers, with a focal positivity of some parabasal cells, was present: five out of nine specimens were positive. Only a few ap optotic bodies were observed. After treatment in almost all specimens it wa s possible to observe a complete bcl-2 negativity with a positivity in only one specimen out of nine. An increase in apoptotic bodies was observed. St atistical analysis showed that the difference between the bcl-2 positivity in the two groups was not statistically significant (P=0.134) while, on the contrary, the difference in the count of the apoptotic bodies between the same two groups was statistically significant (P = 0.0193). Tn conclusion, the data obtained from this pilot study show that good results can be obtai ned with the topical use of 13-cis-retinoic acid. (C) 1999 Elsevier Science Ltd. All rights reserved.