RB1 and neoplasm: E6 targets cellular p53, which is a major cellular tumor-suppressor protein and binds and degrades p53 [91] while E7 complexes with protein members of the retinoblastoma family of tumor suppressors, which control the cell cycle, i.e., pRb, p107 and p130 and this results in their phosphorylation and the release of E2F transcription factors that promote progression of the cell cycle [92].