RAD9A and lung cancer: Another study indicated that hRAD9 is a potential tumor suppressor in breast and lung cancers, which could upregulate p21 expression independent of p53.39 In addition, other factors, such as miR-512-5p,37 miR-132/212,38 and N-myc downstream regulated gene 1,41 were reported to control p21 expression in a p53-independent manner.