Using 144 fixed cervical tissue specimens, pathologists successfully detected p16, Ki-67, ProEx C (novel marker of MCM2 and TOP2A proteins), and p53 in high grade squamous intraepithelial lesions, of which p16, ProEx C, and Cyclin D1 correlated well with the severity of the lesion. This evidence concerns the gene CDKN2A and squamous cell intraepithelial neoplasia.