Detection and typing of human papillomavirus DNA in uterine cervices with coexistent grade I and grade III intraepithelial neoplasia: biologic progression or independent lesions?

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.