Rb phosphorylated by CDK2 is an effector of p38 mitogen-activated protein kinase (MAPK) signal and a regulator of resisting CDK4 and CDK6 suppression.89 Secondly, Rb inactivation relieves the expression of cell state determinants, promotes lineage infidelity, and increases the acquisition of metastasis ability.90 The high phosphorylation level of Rb controls its association with early region 2 binding factor (E2F) and depresses its tumor suppressive properties. Here, RB1 is linked to neoplasm.