PURPOSE: to compare three methods for the detection of HPV infection and to determine the prevalence of the genotypes found. METHODS: a total of 120 cervical scrape samples from patients with cervical intraepithelial neoplasia were analyzed by the conventional polymerase chain reaction using the MY09/11 and GP05+/06+ primers, and by the Nested polymerase chain reaction. The samples were subjected to DNA amplification with the GH20 and PC04 primers (β-globin) to verify DNA quality and also by polymerase chain reaction and Nested polymerase chain reaction. The amplicons were visualized in 1.2% agarose gel stained with Blue Green Loading Dye I. Positive samples also were sequenced using the automatic DNA sequencer "MegaBACE 1000". The Χ2 and Fisher tests were used for statistical analysis with the level of significance set at 5%. RESULTS: fifteen samples were eliminated from the study because they failed to amplify the β-globin gene. Of the remaining samples, 40% (42/105) were positive using primers MY09/11, 98% (103/105) using primers GP05+/06+, and 92% (97/105) using Nested-PCR. With the MY09/11 and GP05+/06+ techniques, it was possible to obtain 100% HPV-positive samples. In this study, the prevalence of the genotypes found was 57, 23, 5, 4 and 3% for HPV genotypes 16, 18, 31, 33 and 56, respectively. HPVs 67 and 83 were present in 2%, and genotypes 6, 11, 58 and candHPV85 were present in 1% each. The prevalence of the more common genotypes (HPV 16 and 18) in this study agrees with that reported worldwide (IC95%=0.4657-0.8976). CONCLUSIONS: to obtain more reliable results, it is necessary the use of more than one primer system to detect HPV infections. We believe that the three techniques studied are important and suitable for the clinical diagnosis of HPV, when they are appropriately combined.
Cervical intraepithelial neoplasm; HPV; Prevalence; Genotype; Molecular biology
