Scientists have sequenced the genomes of two tumors from the same breast cancer patient--a primary tumor and a metastatic tumor that occurred nine years later--illuminating some of the genetic changes that trigger the progression of cancer. The initial findings suggest that both primary cancers and the process of metastasis--the spread of cancer cells--are more complicated and more variable than expected, which means that successful cancer treatment might ultimately require a combination of drugs targeted to different mutations.
The project is also a testament to how easy it has become to sequence a human genome. The researchers, from the British Columbia Cancer Agency, in Vancouver, now plan to sequence the tumor genomes of more than 250 additional patients over the next year. "We are sequencing dozens of tumors a week now," says Samuel Aparicio, the scientist who led the study.
The decline in DNA sequencing costs from hundreds of millions of dollars per person to several thousands of dollars has suddenly made many types of scientific investigation possible. By doing sequencing of tumors at different stages in large numbers of patients scientists will develop a much better picture of which mutations occur in people to cause their cancers become more malignant and deadly. This will lead to treatments aimed at the most deadly mutations.
The amount of data involved in this sort of research is enormous. Each sequencing turns up data for a few billion DNA letters. A cancer patient could get sequencing done at each stage of their cancer. With about 1.6 million people in the United States alone suffering from cancer the total amount of complete genome sequencing that will get done just for cancer patients will equal at least that number per year in order to track existing cancers thru stages of development.
|Share |||Randall Parker, 2009 October 16 12:01 AM Biotech Cancer|