RB proteins restrain the cell cycle and act as tumor suppressors by interacting with the E2F transcription factors and, in the case of RBL2/p130 and RBL1/p107, by binding to the Multivulva class B (MuVB) core to form the transcriptional repressor DREAM (DP, Rb-like, E2F and MuvB) complex [2,3]. The gene discussed is RB1; the disease is neoplasm.