SCREENING THE BLOOD FOR CANCER: Almost all cancers form through the mutation of genes that control the growth of cells. Because of this, as cancers grow, they shed fragments of DNA into the bloodstream. A new test measures levels of DNA from tumors that end up in the bloodstream. Researchers say the test can not only detect the presence of a tumor; it can also track its progress. A study assessing the test involved 18 patients with colorectal cancer. To test the patients, researchers first identified the mutations present in each patient's cancer. They then used a method called BEAMing to search for related mutant tumor DNA in the patients' plasma. In all 18 patients, the same mutations detected in their tissue were found in their plasma. The test also measures the level of tumor DNA circulating in the blood. The higher the level of mutant DNA, the more advanced the cancer.
Doctors hope the test will also be able to predict who is susceptible to cancer and, when a patient gets cancer, if it will recur. "We want to say with as much certainty as we can who will recur and who won't recur, because if we find out with good certainty who will recur, those patients are the ones to whom we recommend chemotherapy," Luis Diaz, M.D., an oncologist at the Johns Hopkins Kimmel Cancer Center in Baltimore, Md., told Ivanhoe. Another test that shows promise for predicting the responsiveness of colorectal cancer patients to treatment is microRNA expression. A recent JAMA study shows high levels of the microRNA called miR-21 may predict poor patient survival.
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Johns Hopkins Kimmel Cancer Center
Valerie Mehl, Public Relations