How does the Rob proteins phosphorylation stage affect the cell cycle and cancer progression? How does the Rob proteins phosphorylation stage affect the cell cycle and cancer progression? Solution The RB(Retinonlastoma) is a tumor-suppressor protein and it has capability to inhibit progressing the cell cycle meticulously at the G1 checkpoint, Hyperphosphorylation of RB trigger release of “E2F” factor. G1 cyclin-cyclin dependent kinases (CDK) complex is mainly involved in the phosphorylation of RB to activate E2F result in initiation of transcription rate to promote DNA synthesis. These events are leading higher DNA synthesis to promote cell division in cell cycle result in tumor cells formation.