RB1 and lung cancer: Transmission of HPV from the oral cavity to the lungs has also been reported.[50] The HPV E6 oncoprotein reduces the tumor suppressor p53 through the E6-associated protein-mediated ubiquitin pathway and results in tumorigenesis in cervical cancer.[51,52] This mechanism was also observed in lung cancer.[53] The HPV E7 oncoprotein promotes degradation of tumor suppressors Rb family via the ubiquitin-proteasomal-mediated pathway and interferes with the relationship of Rb family protein and E2F transcription family, hence inducing tumorigenesis.