Overexpression of CRM1 leads to increased nuclear export; as such, with increased activity of shuttling proteins out of the nucleus, CRM1 is able to evade growth suppressors and sustain proliferative signaling, two of the Hallmarks of Cancer, by shuttling tumor suppressor genes such as p21, p53, and RB, out of the nucleus, allowing for unchecked growth of the cancer cell and resistance to cell death, another Hallmark of Cancer. This evidence concerns the gene RB1 and cancer.