Several studies identified that CDK-RB-E2F pathwaywas vital for controlling cell proliferation, while others assigned additional roles forthis pathway in angiogenesis, metastasis and cancer progression, particularly in BC (29).In addition to Rb, cell cycle checkpoints were crucial in cancer progression, so thatdysregulation of the checkpoints led to an uncontrolled proliferation (30). Here, RB1 is linked to cancer.