TP53 and neoplasm: Viral oncoproteins from viruses like simian virus 40 (SV40) and human papillomavirus (HPV) E6 and E7 deactivate crucial tumor-suppressor proteins such as p53, retinoblastoma protein (pRb), p16INK4a, and p21WAF1/CIP1, which are vital for inducing senescence, controlling cell division, and apoptosis.