CDKN2A and cervical intraepithelial neoplasia: When studying the expression of CK7, CK19, and p16 in 25 cases of high-grade intraepithelial neoplasia of the cervix (CIN3) and in 30 cases of squamous cell carcinoma, Lee at al. found that the expression of CK19, p16, and HPV was positive in all cases of CIN3 and squamous cell cervical cancer, while the expression CK7 was positive in all cases of CIN3 and in 66% of cases of squamous cell carcinoma.