Reação em cadeia da polimerase no diagnóstico e prevalência do papilomavírus

Abstract

Câncer of the uterine cervix is the second cause of death among women worldwide. Among the risk factors for cervical câncer, human papillomavirus (HPV) is the most important one, being present in approximately 100% of the tumors. The polymerase chain reaction (PCR) is the most sensitive test for the diagnosis of HPV in the female genital tract, but factors such as primers and detection systens may affect PCR results, and the final diagnosis of HPV infection. OBJECTIVES: To evaluate the sensitivity of agarose and polyacrylamide gels in the diagnosis of HPV by PCR in smears from the human uterine cervix, to determine the prevalence of HPV by combining the two pairs of primers (MY09/MY11 and GP5+/GP6+), and to compare the results with those obtained with each primer separately. MATERIAL AND METHOD: Eighty-six samples of cervix secretion were studied. Mean patient age was 32 years and 6 months. Each sample was submitted to four PCR procedures using the specific primers MY09/MY11 and GP5+/GP6+ which amplify conserved L1 regions. and then evaluated on 1.5% agarose gel ( stained with Ethidium bromide and visualized under the UV light) and later visualized on 10% polyacrylamide gel (stained with silver nitrate). Data were analyzed statistically by the McMenar test, the z test and the Kappa index, with the levei of significance of p = 0.05.XIV RESULTS: Of the samples from the 86 patients evaluated, 14 (16.27%) were positive to MY09/MY11 on the agarose gel and 20 (23.25%) were positive on the polyacrylamide gel, which detected all the samples that were positive on the agarose gel plus six new ones. With the GP5+/GP6+ primer, 15 samples (17.44%) were positive on agarose gel and 38 (44.18%) were positive on polyacrylamide gel, which detected all the samples that were positive on the agarose gel plus 23 new ones. When the two primers were used in combination, the prevalence was 31.39% on agarose gel with 27 positive samples, but the total prevalence was 48 positive samples (55.81%), obtained with the combination of the two pairs of primers on polyacrylamide gel. CONCLUSION: The polyacrylamide gel presented greater resolution on than the agarose gel system with both sets of primers, GP+ and MY, for the HPV detection. The combination of both markers and gel systens increased HPV prevalence.