Scientists have made a major advance in understanding a gene regulator that contributes to some of the deadliest cancers in humans. Their research paves the way for the development of new cancer therapies. The scientists have elucidated the 3-D structure of a key segment of p300/CBP, one of the most studied enzymes in the HAT family. Aberrant p300/CBP activity contributes to pancreatic, colon, and lung cancer and also can suppress tumors.