p53 (or tp53) is a gene vital to many forms of life, including humans. It codes for a protein which suppresses cancer. It has been called "the guardian of the genome".
The p53 gene is the most frequently mutated gene (>50%) in human cancer. Its protein product binds to DNA and regulates gene expression to prevent mutations of the genome.
p53 protein (TP53) is at low levels in human embryonic stem cells (hESCs). This allows the most important cell division to proceed rapidly.