Today's cancer chemotherapy consists of little more than a dismal array of toxic drugs that kill healthy cells along with cancerous ones. Physicians must often play a deadly game of trial and error, hoping to find the right dose of the right medicine before time runs out. But a pipeline of new molecular drugs targeting so-called epigenetic phenomena could change that. These treatments could mark a path to a new array of cancer prevention strategies less toxic to the body.

The term "epigenetics" refers to the study of changes in gene expression that do not involve changes in the genetic code; they include an expanding roster of subtle molecular modifications that tell cells which genes to activate (or transcribe) and which to suppress. In cancer cells, these small-molecule regulators can act like broken dimmer switches, turning genes that promote cell growth all the way up and those that suppress tumors all the way down. By comparing the epigenetic patterns of cancerous cells with those of healthy cells, scientists are trying to identify the abnormalities tied to tumor growth. Research has led to the discovery of epigenetic culprits in many cancers, including those found in the colon, prostate, breast and blood.