Human papillomaviruses (HPV) in gynaecological cytology: from molecular biology to clinical testing.

Molecular epidemiological and pathological studies show that different HPV types are associated with different cervical lesions allowing classification of the viruses into types associated with 'high', 'intermediate' and 'low' risk of cervical neoplasia. However, HPV infection often regresses and, where it is associated with neoplasia, is an early event. This suggests that other factors are involved in the carcinogenic process, and there is some mechanistic basis for the interaction of epidemiologically defined factors with HPV infection in the process of cervical carcinogenesis. With the refinement of techniques for HPV detection in clinical material, HPV testing is now a realistic possibility, but how this should be performed and in what clinical situation(s) is still uncertain. Particular areas of interest are: (i) the assessment of patients with borderline cytological changes or mild dyskaryosis; and (ii) the definition of those patients at greater risk of invasive disease. Clinical trials are needed before the utility of HPV testing can be properly assessed.