Objective: To examine the HPV type infection of cervical cone specimens with coexistent CIN1 and CIN3 lesions, in order to define if coexistence of low- and high-grade lesions in the same cervix represent different stages of evolution in a continuing process that is caused by a single viral type or independent lesions induced by different HPV types.
Study design: The examined material included 43 cases with coexistent CIN1 and CIN3 in the cone biopsy specimen. Detection and typing of HPV was made by RFLP-PCR.
Results: All CIN1 lesions were HPV positive, while three CIN3 lesions were HPV-negative. The proportion of agreement of the HPV type in the two lesions, excluding negative cases (n = 40), was 60% (95% confidence interval: 43.3-75.1). HPV 16 was the most common type in both CIN3 (56.8%) and CIN1 (46.5%).
Conclusions: The so-called morphologic progression of CIN is not always synonymous with biologic progression, since many coexistent CIN lesions are caused by different HPV types, and so represent different cell clones. Clonality of coexistent CIN lesions may be implicated in the evolution of CIN as other recent studies have shown.