TP53 and neoplasm: p53 has been found to upregulate the expression of the miR-34 cluster which is reported to mediate several tumor suppressive functions of p53 including senescence, cell cycle arrest, and apoptosis (Bommer et al., 2007; Chang et al., 2007; He et al., 2007; Raver-Shapira et al., 2007; Tarasov et al., 2007).