RB1 and neoplasm: The Rb protein is an inhibitor of the cell cycle and a master regulator in the progression from G1 to S-phase.44 For HAdV-C5, a 24-bp deletion in one Rb-binding domain of E1A gene has previously shown to generate a mutant Ad with selective replication in tumor cells.45 Therefore, the E1A gene of AdV-lumc007 was analyzed for putative Rb-binding sites (Fig. 4D).