[Histologic studies on the frequency of Candida invasion in precancerous oral leukoplakia].

Out of 243 biopsies taken from oral leukoplakias of 202 patients we found 53 precancerous lesions (21,8%). According to different degrees of epithelial dysplasia, we differentiated the lesions into three histological grades of precancerosis and examined them, in additon to previous mykologic investigations on oral smears, as to the occurrence of Candida species in the epithelium. A significant increase (p less than or equal to 5%) of Candida occurrence parallel to the grade of the precancerous dysplasia could be demonstrated. The rates of Candida invasion run from 10% in dysplasia grade 1 to 31% in grade 2, and 56% in grade 3. The results indicate a lowered resistence of precancerous lesions against Candida, which allows the microorganisms to invade the displastic epithelium. Our findings are in favour of the view that Candida acts not as a co-carcinogenic agent but points to a weakened defence activity of the host cellular immune system.