The overexpression of p16INK4a has been linked to the severity of premalignant lesions, i.e. there is a greater expression of this protein in CIN2 and CIN3 (which corresponds to a high-grade squamous intraepithelial lesions-HSIL) than in CIN1 which corresponds to a low-grade squamous intraepithelial lesions-LSIL [32], [33]. Here, CDKN2A is linked to squamous cell intraepithelial neoplasia.