RB1 and retinoblastoma: However, when RB1 is inactivated, this inhibitory control is lost, allowing TR-mediated gene expression to proceed unchecked [320].This mechanism suggests that the TH signaling pathway may influence tumorigenesis in retinoblastoma by regulating cell proliferation and differentiation, closely interacting with the tumor-suppressive functions of Rb protein, and providing new perspectives for studying tumor development and progression [320] (Fig. 7).