CDKN1A and neoplasm: A major driver of cellular transformation is the loss of proper control of the mammalian cell cycle.31 Disturbance of this balance by disrupting the program that regulates cell cycle entry can result in the transformation of normal cells into tumor cells.32, 33, 34 As a key regulator of cell cycle progression at G1/S transition, p21 has a critical role in tumorigenesis.34, 35, 36, 37 Our study demonstrated that downregulation of CDC27 can lead to G1/S transition arrest via the accumulation of p21 (Figures 3b and d).