The p53 Pathway Encounters the MicroRNA World

The p53 protein is a transcription factor that regulates multiple cellular processes in human and other high eukaryotes including cell proliferation, differentiation, cell cycle, and metabolism. The central roles played by p53 in tumor development have drawn extensive studies on p53 activation and inactivation. The regulation of p53 and its pathway, as well as its transactivational targets is of prime importance in the understanding of tumorigenesis. Recently, microRNAs (miRNAs) have been reported to be directly transactivated by p53. Equally, p53 and components of its pathway have been shown to be targeted by miRNA thereby affecting p53 activities. In this review, we focus our discussion on the biological and pathological roles of miRNAs in the p53 pathway.