Human papillomavirus type 16 and 18 variants

Variants of human papillomavirus (HPV) 16 and 18 persist longer in people whose ancestors are from the same geographical area as the virus, according to a study in the August 2 issue of the Journal of the National Cancer Institute.

Around 100 types of HPV have been identified to date. Within a type, several genetic variants exist, many of which can be classified by geographical region. HPV infection, particularly infection with HPV types 16 and 18, can lead to cervical cancer.

Long Fu Xi, M.D., Ph.D., of the University of Washington in Seattle, and colleagues studied approximately 1,100 women infected with HPV 16 and/or 18 from the Atypical Squamous Cells of Undetermined Significant/Low-Grade Squamous Intraepithelial Lesion Triage Study. The women were examined for HPV every 6 months for 2 years.

Variants of HPV16 and 18 types persisted longer when they came from the same geographical area as the ancestors of the person infected. Infection with African variants lasted longer in African American women, and infection with European variants lasted longer in white women. Women were also more likely to be infected with an HPV variant from the area their ancestors came from.

The authors write, "Given that women with persistent HPV16 or HPV18 infections are at increased risk of cervical cancer, future studies should be conducted to examine possible mechanisms involving variant-specific immune evasion and their potential clinical and therapeutic implications."

In an accompanying editorial, Robert D. Burk, M.D., of the Albert Einstein College of Medicine in Bronx, NY, and Rob DeSalle, Ph.D., of the American Museum of Natural History in New York, write, "The HPV16 and HPV18 variants appear to be in a 'tango' with some unknown characteristics of the human genome associated with race. The 'tangle' is trying to figure out what these factors might be and how the relationships among virus variation, host variation, and persistence lead to cancer."