RB1 and neoplasm: After the virus enters the tumor cell, the early gene in the E1 region initiates transcription and translation, and the E1A protein binds to the Rb protein, phosphorylating the Rb protein and releasing the transcription factor E2F, activating the cell cycle to bring the tumor cell into the S-phase, increasing the replication of the virus [17], eventually causing lysis of these cells.