Genetics Hold Promise, Challenges for C...(more than 210 different cancer types. T...),Health

It all looks very promising. But Lichtenfeld said that every DNA discovery has its downside, too.

"The more that we learn, the more complex it is going to get," he said. Indeed, the mapping of the breast and colon cancer genomes revealed that not only were the two cancers radically different in their origins, but that each tumor differed greatly between patients.

It's quickly become a very tangled web, experts say, but that's an inevitable part of the science.

"There may be a period of greatly evolving complexity that we have to get through which will only be sorted out by doing larger numbers across more genes," Futreal said.

Complicating matters further is the emerging field of epigenetics -- the study of how genes change their activity as they respond to their environment.

Still, certain "commonalities" could simplify things. Futreal pointed out that even though hundreds of genes can go awry and cause a cancer, many of these mutations will target the same cellular pathway. So, treatments that repair those broken pathways could fix a host of tumor types, he reasoned.

Today, however, only a small minority of cancer patients are directly benefiting from gene-based diagnostics or treatments. Those include women who carry the BRCA 1 and BRCA 2 breast cancer mutations, patients with chronic myelogenous leukemia (CML) who can take Gleevec, and early stage lung cancer patients who may soon benefit from those new prognostic tests.