Usefulness of combining universal oligonucleotides in detecting human papillomavirus in cervical cancer and premalignant lesions

Objective. To determine the prevalence of human papillomavirus (HPV) infection at different stages of the natural history of cervical cancer. Also, to optimize its detection by means of different sets of general primers. Material and Methods. A descriptive, cross-sectional study was conducted between January and December 1999. Samples were processed and analyzed at the Instituto Nacional de Cancerologia (National Cancerology Institute) in Mexico City. A comparative analysis was performed using Student's t for continuous values and the chi-squared test for proportions. A contingency analysis was made between biopsy and cervical exudates with the Kappa statistic. HPV detection was done by PCR with general primers which recognize different regions of the L I gene (MY09/11; GP5/6; L1C1/2) and with HPV16- and HPV18- specific primers, as well as direct sequencing of PCR products. Results. In total, 154 samples were analyzed: 65 (42.2%) of them showed normal cytology; 45 (29.2%) high and low grade lesions; and 44 (28.6%) invasive cervical cancer. HPV was detected in 95.5% of invasive cervical cancers, in 91.6% of high grade lesions, in 66.7% of low grade lesions, and in 23.1% of normal smears, by PCR with at least one set of oligonucleotide primers. HPV detection was more efficient in biopsy specimens than in cervical scrapes. The total percentage of HPV detection using only one set of universal oligonucleotides (37.6%)increased to 60.4% when the other two sets of universal oligonucleotides were used. Conclusions. The frequency of high risk HPV is high even in women with reported normal cytology. HPV detection improves when different sets of general primers directed to the L1 region are used. HPV DNA screening in cervical scrapes may be a good alternative HPV diagnostic tool when the samples are appropriately taken. The English version of this paper is available at: http://www.insp.mx/salud/index.html.