CDKN1A and acute lymphoblastic leukemia: Further, treatment of ALL leukemic cells with sulforaphane resulted in dose dependent apoptosis and G2/M cell cycle arrest, which was associated with the activation of caspases (3, 8 and 9), inactivation of PARP, p53-independent upregulation of p21CIP1/WAF1, and inhibition of the Cdc2/Cyclin B1 complex.