RB1 and cancer: Simultaneously and following our studies on the antitumor effects of GSK3β inhibition, similar observations from other laboratories were reported for various cancer types with underlying mechanisms that included regulation by GSK3β inhibition of several pathways mediated by p53, Rb, p27Kip1, cyclin-dependent kinase (CDK), cyclin D1, c-Myc, and NF-κB [78].