Despite this as far as normal cervical epithelium is p16INK4a-negative and the ratio p16INK4a-positive/ p16INK4a-negative samples increases at the advanced stages of CINs and carcinomas application of immunohisto-/cytochemical test for p16INK4a may be regarded as an additional (optional) test for early detection of precancerous lesions in cervical epithelium. This evidence concerns the gene CDKN2A and carcinoma.