Eight Human Papillomavirus Types Cause Most Cervical Cancers

Eight human papillomavirus (HPV) types cause more than 90% of all cervical cancers worldwide, and three types cause 94% of cervical adenocarcinomas.

Polymerase chain reaction (PCR) and DNA testing were used to identify the HPV genotypes present in tissue samples collected from a large number of patients who had invasive cervical cancer.

A massive multinational cervical cancer study was carried out at the Catalan Institute of Oncology (Barcelona, Spain) where paraffin-embedded samples of histologically confirmed cases of invasive cervical cancer were tested. The samples were collected from 38 countries in Europe, North America, central South America, Africa, Asia, and Oceania. HPV detection was done by use of PCR with short PCR fragment (SPF-10) broad-spectrum primers followed by DNA enzyme immunoassay and genotyping with a reverse-hybridization line probe assay. Sequence analysis was done to characterize HPV-positive samples with unknown HPV types. Data analyses included algorithms of multiple infections to estimate type-specific relative contributions.

The retrospective cross-sectional study collected samples from 10,575 cases of invasive cervical cancer diagnosed between 1949 and 2009 and 8,977 (85%) of these were positive for HPV DNA. The eight most common HPV types identified were, in descending order of frequency: 16, 18, 45, 33, 31, 52, 58, and 35. HPV types 16, 18, and 45 were detected in 443 of 470 cases (94%) of cervical adenocarcinomas. Unknown HPV types that were identified with sequence analysis were 26, 30, 61, 67, 69, 82, and 91 in 103 (1%) of 8,977 cases of invasive cervical cancer. Women with invasive cervical cancers related to HPV types 16, 18, or 45 presented at a younger mean age than did those with other HPV types. The results suggest that type-specific high-risk HPV-DNA-based screening tests and protocols should focus on HPV types 16, 18, and 45.

Silvia de Sanjose, M.D., the lead author said, "HPV types 16, 18, 31, 33, 34, 45, 52, and 58 should be given priority when the cross-protective effects of current vaccines are assessed and for formulation of recommendations for the use of second-generation polyvalent HPV vaccines." The study was published October 15 2010, in the journal Lancet Oncology.

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Catalan Institute of Oncology