Parallel sections from 423 randomly selected blocks representing biopsies of 178 women with the diagnosis of cervical dysplasia and/or erosion were stained for p16 polypeptide. The p16/INK4A (inhibitory kinase 4) protein is a cellular division regulator, expression of which increases in the presence of oncoprotein E7, encoded by human papillomavirus (HPV). Expression of p16 protein was seen in the nuclei and cytoplasm of dysplastic squamous epithelium cells as well as in carcinoma cells. In 16.6% of erosion cases, the p16 antigen was present in the basal and suprabasal layer of the surrounding squamous epithelium revealing features of CIN I/LSIL. In CIN I/LSIL as classified by HE staining, the p16 antigen was found in 65 out of 80 (81%) cases. The p16 protein was typically seen in dysplastic basal and suprabasal cells encompassing a confluent layer in the lowest third segment of stratified epithelium. In CIN II and CIN III grouped as HSIL, the positive rate of p16 antigen presence was 95% (in 45 cases out of 47) and/or 100% (in each of 27 cases), respectively. The typical sign of p16 antigen distribution in HSIL was its staining over two thirds and/or throughout the whole dysplastic epithelium. Extensive staining for p16 antigen was registered within nuclei as well as cytoplasm of neoplastic cells in all 6 cervical squamous cell carcinomas, which were examined in many sections when being used as positive controls. Based on our experience, we consider the p16 antigen staining a helpful tool indicating dysplastic cells and estimating their extent.

Laboratórium patologickej anatómie Alpha Medical a s Martin