According to a study published in the Journal of Medical Virology, a higher concentration of human papillomavirus type 16 or 18 in cervical cells tends to be with linked more severe cervical abnormalities.
Nearly 10,000 women are diagnosed with cervical cancer in the United States each year. Cervical cancer is generally preceded by precancerous changes to the cervix known as cervical intraepithelial neoplasia (CIN). The severity of CIN is graded on a scale of 1 to 3, with 3 being the most severe. CIN2 and CIN3 are considered “high-grade” CIN and may progress to cancer if not treated.
Human papillomaviruses (HPV) consist of more than 100 different viruses. Some types of HPV cause warts on the hands or feet; others cause genital warts; and some have been linked with cancer, most notably cervical cancer. The types of HPV most commonly linked with cervical cancer are HPV 16 and HPV 18, but several other high-risk types contribute to cancer as well.
The recognition that specific types of HPV are the cause of cervical cancer led to the development of a vaccine against four common types of HPV and a test to identify infection with several high-risk types of HPV.
Among women infected with HPV, the concentration of virus (viral load) can vary. To evaluate whether higher virus concentration is linked with more severe cervical abnormalities, researchers in France conducted a study among 151 women referred for colposcopic examination of the cervix. Ninety-seven of the women were receiving additional diagnostic evaluation after an abnormal Pap test (group 1), and 54 women were receiving follow-up after treatment of cervical abnormalities (group 2). Virus concentrations were measured in samples of cervical cells.
- Among women between the ages of 30 and 40 years, HPV 16 concentrations were significantly higher in high-grade CIN than in low-grade CIN. This same trend was observed for HPV 18 concentrations, but only among women in group 1.
The researchers conclude that higher concentrations of HPV 16 and HPV 18 tend to be linked with more severe cervical abnormalities. Information about virus concentration may help guide the management of cervical abnormalities.
Reference: Carcopino X, Henry M, Benmoura D et al. Determination of HPV Type 16 and 18 Viral Load in Cervical Smears of Women Referred to Colposcopy. Journal of Medical Virology. 2006;78:1131-1140.