Too Slow for Cancer
Bless that reporter who cut to the chase at the press conference last month announcing the new project to map the genes of individual cancers. The Cancer Genome Atlas, said National Institutes of Health officials, will blow open the instruction book on cancer. But if this venture is so revolutionary, the reporter asked, why is its pace so agonizingly slow? For the 40 percent of Americans who will face cancer, and for nearly everybody who's been convinced we are at the dawn of a new age of gene-targeted therapies, his question couldn't be more right on.
The Atlas should be the hottest thing in genome exploration since the map of the normal human genome was completed in 2003. But insecurity about a slow-growing NIH budget and a cultural bias against big science projects have frozen a bold-footed move into a tentative tiptoe: A three-year pilot studying only two to three as-yet-to-be-determined cancers (wait until that selection process starts!) will cost the National Cancer Institute $17 million of its annual $5 billion budget and the National Human Genome Research Institute an additional $17 million. Only if the pilot reaches unnamed milestones will the Atlas be stretched into a decade-long, billion-dollar study of 50 cancers--out of over 200.
Cancer is a disease of our genes. Chemical glitches develop across our DNA strands and transform normal cells into a mass of perpetually growing ones, poised to march through the body in a deadly takeover. But these glitches have turned out to be unexpectedly numerous, complex, and variable, even across some cancers with the same look. That explains why one tumor responds to treatment and another of the same type doesn't. Or why one cancer pokes along for years and another kills in a flash. But the explanation remains hidden within the many cancer genomes and their mysterious behavior.
Because of this knowledge gap, cancer treatments are mostly scattershot with lots of collateral damage--and are often fruitless. Francis Collins, who leads the NHGRI, bemoans the darkness that envelops cancer and limits its research. He compares it to searching for keys on a dark street where there's only one lamppost. You search where there's light, and it's sheer luck if you find them. For cancer, he says, we need "a thousand lampposts to shed light on the darkness of our ignorance." The Atlas is just that. We have the means, we have the brainpower, and we have ever better and cheaper technology to get there.
And we have witnessed the power of knowing about even one or two toxic genes in a cancer cell. The designer drug Gleevec puts one form of leukemia into remission by targeting a DNA error once thought to be a result of the cancer, not its cause. The new drugs Tarceva and Iressa block the handi-work of another gene gone bad and can extend a one-year survival with lung cancer to two--but only in the 10 percent of patients with the gene. A small victory perhaps, considering we have an incomplete blueprint of what's really happening in those cells. But a victory nonetheless for the 10 percent of patients whose survival increases 100 percent. As NIH Director Elias Zerhouni says, cancer research is hamstrung from moving on a broader front because of limited genomic insight.