The proportion of p16 expression increased with the severity of histological grade. p16 positivity was 2% (95% CI: 0.2-5%) in normal histology, 12% (95% CI: 2-27%) in low-grade squamous intraepithelial lesions (LSILs)/AIN1 (excluding condylomas), 7% (95% CI: 2-13%) in all LSIL (AIN1/LSIL/condyloma), 76% (95% CI: 61-88%) in AIN2, and 90% (95% CI: 82-95%) in AIN3.
There was a correspondence among HPV genotypes in invasive and associated PeIN. p16 was positive in the majority of HPV-positive lesions except condylomas containing LR-HPV. p16 was usually negative in squamous hyperplasia, differentiated PeIN, and low-grade keratinizing variants of squamous cell carcinomas.
We studied growth factor receptors, p16 and Ki67 expression, by in situ hybridization, fluorescent in situ hybridization (FISH) and chromogen in situ hybridization (CISH), immunocytochemistry, and morphological quantification in 226 lesions, either infected by HPV6 and 11 (31 condylomas acuminata) or infected with oncogenic HPVs (48 invasive cancers, 147 anal intraepithelial neoplasias).No HER2/neu was detected.