Cancer epigenetics is hot. At the annual meeting of the American Association for Cancer Research in April, once-obscure principal investigators were feted by gaggles of admirers and many poster presenters mobbed by the curious. "It's one of the hottest areas of basic biology," said Paul Workman, Ph.D., director of cancer therapeutics at Cancer Research U.K.

The decoding of the human genome nearly a decade ago fueled expectations that an understanding of all human hereditary influences was within sight. But the connections between genes and, say, disease turned out to be far more complicated than imagined.