How to crack the cancer code
In 2003, 13 years and $2.6 billion after it started, the Human Genome Project completed the sequence of nearly all of the 2.9 billion letters of genetic code that make up the human being.
Now researchers are tackling what may be an even more ambitious challenge – developing an “atlas” that describes the genetic characteristics of the more than 200 different types of cancer.
In 2006 the National Cancer Institute and the National Human Genome Research Institute announced that lung, brain (glioblastoma) and ovarian cancers will be studied during a three-year pilot to determine the feasibility of a full-scale Cancer Genome Atlas project.
Patients will be asked to donate a small portion of tumor tissue that has been removed as part of their treatment. The biospecimens will be processed at a central facility, and distributed to cancer genome characterization centers, which will determine which genes are selectively turned on or off in the tumors.
Genome sequencing centers will conduct further investigations, looking for changes in the DNA sequence that may be associated with specific cancer types. This information will be entered into public databases so that researchers ultimately can use it to improve cancer diagnosis, treatment and prevention.
The attempt to redefine cancer by its genetic code has been made possible by phenomenal technological advances during the past two decades.
In the mid-1980s, a scientist could spend a day determining the sequence of 50 to 100 nucleotide bases, the four “letters” (adenine, guanine, cytosine and thymine) that make up the DNA code, at a cost of $10 per base.
The current generation of sequencing machines can sequence one million bases a day for about 50 cents a base. A new generation of machines – now being tested – may increase the output to 500 million bases a day at a cost that is 100 times lower.
The machines are not cheap, however. Both the current and new machines cost about $300,000 each.
To succeed, The Cancer Genome Atlas project must push the technology even further so that researchers can decipher the complex genetic and molecular interactions that underlie malignant growth, and at a reasonable cost.
For more information, go to http://cancergenome.nih.gov.
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