CDKN2A and squamous cell intraepithelial neoplasia: p16 overexpression indicates high-risk HPV infection, not only in uterine cervical carcinoma and head and neck carcinoma, but also in high-grade squamous intraepithelial lesions (HSILs) of the vulvovaginal and anogenital regions; therefore, p16 is used as a diagnostic marker for both HSIL and invasive squamous cell carcinoma [1, 15].