CDKN2A and neoplasm: In HPV-associated cervical carcinoma, the situation is less clear since some studies showed that the tumor suppressor activity of these proteins is overcome through the action of the viral oncogenes E6/E7 without any change in their expression level [22], others showed that this applies to p21waf and p27kip1 only whereas p16INK4A is usually down regulated [22-24].