DNA Tests Instead of Colonoscopies

Colorectal cancer, or colon cancer, is the second most common cancer in the United States. It leads to fifty thousand deaths every year and it costs around fourteen billion dollars to treat. Colon cancer can be removed if it was detected early but many people do not get a colonoscopy when requested by their doctor. But there is a newer, faster way to detect colon cancer, DNA tests. DNA tests began to develop when Dr. Bert Vogelstein of Hopkins University first discovered the mutations in DNA that led from a colon polyp, the stage of cancer that has the highest possibility of prevention, to the complete cancer. Along with testing for DNA mutations, testing highly methylated DNA for colon cancer has also been developed. Methylated DNA is the genes that methyl was added to, to turn it off. This usually happens more often on the tumor suppressor genes of a cancer cell than on the other genes. Exact Sciences believes that by testing for methylated DNA at four markers, they will be able to make an exact diagnosis. But the percentage of making the right diagnosis is lower in real life because they were testing the DNA of a tumor and not the DNA in stool samples. This four-marker test is estimated to be less than three hundred dollars and the sample needed can be collected at home, making it more convenient for patients. Even though testing for methylated DNA is promising, people such as Dr. Vogelstein still support testing for DNA mutations more because “they are what is driving the tumor”. Not only can methylated DNA testing be used to diagnose colorectal cancer but it can possibly be used in the future for cancers such as pancreas and esophagus by testing other markers in the DNA.

This article relates to biology because it involves DNA. It involves the testing of DNA mutations, change in the DNA of a gene, to detect colon cancer. It also involves the process of methylation, the attachment of methyl to a gene to turn it off, to prevent the gene from being expressed. Another reason why this article relates to science is because of its association with cancer, a disease characterized by uncontrolled growth of cells.

This information is important to us because cancer is affecting more and more people every year. It is very important to learn more about this disease and possibly find a cure or at least prevent it. Testing for DNA mutations and also testing methylated DNA to detect colorectal cancer may be a crucial step in diagnosing other cancers as well.

Source: http://www.nytimes.com/2010/08/10/health/10cancer.html?ref=science