Discovered in 1979, p53—sometimes referred to as “The Guardian Angel of the Genome”—is a gene that, when a cell’s DNA is damaged, acts as an “emergency brake” to halt the resulting cycle of cell division that can lead to tumor growth and cancer. It also acts as an executioner, programming damaged cells to self-destruct before their altered DNA can be replicated. However, when it mutates, p53 can lose its suppressive powers or have the devastating effect of actually promoting abnormal cell growth. Indeed, p53 is the most commonly mutated gene found in human tumors. Scientists have discovered a compound that could restore function to a mutant p53. Such a discovery may lead to the development of anti-cancer drugs targeting the mutant p53 gene.