Combined p53 and retinoblastoma protein detection identifies persistent and regressive cervical high-grade squamous intraepithelial lesions.

Most cervical high-grade squamous intraepithelial lesions (HSILs) persist, but approximately one third regress (ie, no HSIL in follow-up biopsies). To identify factors related to histologic proven persistence or regression. Twenty-eight small histologic (marker) biopsies with adequate follow-up were analyzed for human papillomavirus (HPV) genotypes and different immunoquantitative proliferation, cell cycle regulation, and differentiation markers. All cases had a biopsy-interval between the marker and first follow-up biopsy of at least 100 days (median, 8.2 months; range, 3.4-22.5 months). Follow-up was classified as regression or persistence. All lesions were high-risk (hr) HPV and p16 positive, 63% for HPV-16 or HPV-16 mixed with other hr genotypes, while 37% had other hrHPV types. The marker biopsies of the persistent HSILs had lower p53 and retinoblastoma protein (pRb) detected in the deep half of the epithelium (P = 0.001 and 0.02, respectively) than nonpersistent HSILs. The degree of positivity of p16, Ki-67, cyclin D1, lesion extent, positivity of the resection margins, and patient age were all unrelated to persistence or regression. Lesions with HPV-16 or mixed-16 genotypes had a significantly lower percentage of pRb (P = 0.02), p53 (P = 0.02), and cyclin D (P = 0.04) positive nuclei in the deep epithelial layers. In agreement with this, type-16 positive HSILs had a lower regression percentage than those with other HPV types, but the difference was not significant. HSILs with combined negativity/low positivity for p53 and pRb protein in small histologic biopsies are highly likely to persist, contrasting those in which one of these cell cycle regulators is strongly positive (p53 > 15%; pRb > 40%).