Reference Manual - IARC Screening Group

Human Papillomavirus and Cervical Cancermonths and then subsided. After 2 years, however, about 10% of thewomen still carried active virus in the vagina and cervix. In this study,the persistent infections were most commonly associated with thevirulent, cancer-linked types of HPV. As discussed below, certain typesof HPV, as well as immune-deficient conditions (e.g., HIV/AIDS), areassociated with persistence of disease.THE VIRUSPapillomaviruses were first recognized many years ago as the cause ofwarts on the hands and feet or condyloma accuminata on the pubic area(penis and urethra in men or vulva and vagina in women). For years,warts were considered mainly bothersome or ugly, rather than aforerunner of cancer. Indeed, the virus types that cause warts on fingersand toes usually are not dangerous. The types that target the face,however, can increase a person’s risk of developing skin cancer. Stillothers, which grow mainly in the mouth and produce pea-sized lumps,can develop into fatal squamous cell cancers (Terai et al. 1999).The papillomavirus is relatively small—just two strands of DNAcontained in a round shell, or envelope, that looks like a golf ball whenenlarged under an electron microscope (Figure 2-1).Figure 2-1. Electron Photomicrograph of Human PapillomavirusSource: Stannard/Photo Researchers 1998.Because HPV cannot be cultured, and a reliable serologic test was notavailable until recently, it has been difficult to collect accurateinformation about the incidence and course of HPV infections. Forexample, prior to the 1990s, the only way cervical infection with HPVcould be detected was by examining cells from Pap smearsmicroscopically or by looking at the cervix through a colposcope. Using2-2 Cervical Cancer Prevention Guidelines for Low-Resource Settings