RESUMO
The purpose of this study was to investigate the prevalence of human papillomavirus 6/11 and 16/18 in patients, with oral lesions clinically diagnosed as leucoplakia, attending the School of Dentistry, University of São Paulo State/UNESP, Brazil. After paraffin embedded process, in the sections staining with H&E, 30 biopsies were screened and separated on 3 groups: 10 oral lesions without dysplasia, 10 with dysplasia, and 10 with invasive squamous cell carcinoma. The lesions with dysplasia were classified in agreement with Van Der Wall's histopathological standard method. Oral lesions were investigated for the presence of human papillomavirus (HPV) by in situ hybridization with wide-spectrum, 6/11 and 16/18 biotinylated probes. HPV 16/18 was found in 20% (n = 2) of the leucoplakia with severe-degree dysplasia. The presence of HPV 16/18 in malignant lesions suggests its importance as a risk factor for oral carcinogenesis.