New research suggests that a universal blood test to detect cancer could be closer than previously thought. By sequencing the normal DNA that a tumor releases into the bloodstream, researchers believe they can develop a single blood test that can detect early tumors as well as advanced cancers.
DNA tests that have been previously used detect tumors by looking for known alterations in cancer genes. Researchers at Johns Hopkins University School of Medicine in Baltimore took these tests a step further. Observations have generally shown that tumor cells in the body almost always have substantially altered chromosomes, like swapped pieces, or extra copies of certain genes. Therefore, a blood test that could detect such chromosomal abnormalities, even without knowing the genetic makeup of the cancer beforehand, could serve as a general test for all types of cancers.
Secondary benefits. These tests, which are able to isolate “free tumor DNA” in blood samples, may also be able to assist in tracking whether a patient’s tumor is responding to treatment, or regrows after surgery. The test could also assist in deciding which drug would be most beneficial for treatment, without having to biopsy the actual tumor.
At this time the tests are not cheap or quick. Each test can cost several thousand dollars, and may take as much as a month to analyze, though the researchers believe the costs will decrease. Experts think these tests are a breakthrough, and that such tests could be available within 5-10 years.
Sources and related articles:
- A Step Toward a Universal Cancer Blood Test (science mag)
- A Blood Test That Screens For Cancer (science.slashdot.org)
- Cancer Screening Via Blood Test And Gene Sequencing (medicalnewstoday.com)
- Genome-Scale Discovery of DNA-Methylation Biomarkers for Blood-Based Detection of Colorectal Cancer (plosone.org)
- Johns Hopkins scientists pair blood test and gene sequencing to detect cancer (eurekalert.org)
- Blood tests to detect brain tumours and possibly prostate cancer (mypersonaltrainerjournal.com)
- Kansas State develops cancer-detecting blood test (kansas.com)