More than 200 researchers investigating colon cancer tumors have found genetic vulnerabilities that could lead to powerful new treatments. The hope is that drugs designed to strike these weak spots will eventually stop a cancer that is now almost inevitably fatal once it has spread.

Scientists increasingly see cancer as a genetic disease defined not so much by where it starts — colon, liver, brain, breast — but by genetic aberrations that are its Achilles’ heel. And with a detailed understanding of which genetic changes make a cancer grow and thrive, they say they can figure out how best to mount an attack. They caution that most of the drugs needed to target the colon cancer mutations have yet to be developed, but they say they are building the road map that they hope will lead them to new treatments.

The colon cancer study, published on Wednesday in Nature, is the first part of a sweeping effort that is expected to produce a flood of discoveries for a wide range of cancers. The colon cancer findings will soon be followed by studies of lung and breast cancers and, later this year, of acute myeloid leukemia. The effort, the $100-million-a-year Cancer Genome Atlas project, is being financed by two government agencies, the National Cancer Institute and the National Human Genome Research Institute.

The colon cancer results, based on a study of 224 tumors, show what may be possible.

“There are so many different ways that you can attack this tumor type,” said Raju Kucherlapati, the principal investigator for the colon cancer project and a professor of genetics and of medicine at Harvard Medical School. “We have an opportunity to completely change the landscape.”