Interestingly, while strong p16 expression is a near universal hallmark of high-risk HPV+ carcinomas of the cervix or oral cavity [32–34], p16 is not expressed in high-risk HPV+ low-grade lesions and variably expressed in higher grade precancerous lesions [44, 45] or lesions caused by low-risk HPV types [32, 46, 47]. This evidence concerns the gene CDKN2A and carcinoma.