In PLoS Biology this week, investigators at MD Anderson Cancer Center and their collaborators show that "p53 plays an active role in promoting differentiation of human embryonic stem cells and opposing self-renewal by regulation of specific target genes and microRNAs." Further, the team writes, "p53 activates expression of miR-34a and miR-145, which in turn repress stem cell factors OCT4, KLF4, LIN28A, and SOX2 and prevent backsliding to pluripotency." and This study "under