CDKN2A and vulvar squamous cell carcinoma: In HPV-associated carcinomas, viral oncoprotein E7 expressed by high-risk α-HPV genotypes functionally inactivates the retinoblastoma protein (pRb), which in turn leads to the overexpression of the p16INK4A (p16) tumor suppressor [21] and the immunohistochemical detection of p16 is often used as a surrogate marker for the high-risk HPV infection in squamous cell carcinomas of the vulva, penis, perianal area, uterine cervix and oropharynx [21, 22].