Hopes that large studies of cancer genomics will justify their high cost by offering a fast-track to cures have been dealt a blow by a series of papers. The controversial Cancer Genome Atlas, run by the US National Institutes of Health, is analysing genetic and epigenetic changes in cancers. Still in its pilot phase, the project could eventually cost up to $1.35 billion. But it does not include ‘functional’ studies that investigate how the mutations aid tumour development and what drugs might target the pathways essential to tumour survival. Yet functional studies are exactly what two papers, from a group led by Bert Vogelstein of the Johns Hopkins School of Medicine in Baltimore, Maryland, suggest are needed. He and others say that the focus should shift from hunting for individual genes that cause certain cancers, to disrupting the broader biological pathways that support cancer growth.
“It is apparent from studies like ours that it is going to be even more difficult than expected to derive real cures,” says Vogelstein. Two papers from his team, plus one from the Cancer Genome Atlas group, appeared on 4 September in Science and Nature. The studies find that individual cancer patients each carry dozens of genetic mutations — an average of 63 alterations in pancreatic cancer and 47 DNA mutations in one type of brain cancer. Similar results have been found in previous studies of other cancers. This makes it unlikely that the cancers will be cured by drugs that target just one or a few genes, the researchers say.