RB1 and neoplasm: BRG1 can bind all three Rb family members (Dunaief et al., 1994), and genetic analysis of human tumors has suggested that BRG1 is a tumor suppressor (Reisman et al., 2009; Medina et al., 2008; Rodriguez-Nieto et al., 2011; Hargreaves and Crabtree, 2011).