Researchers have developed a blood test that can detect cancer and identify its location in the body. The test, which involves the use of a computer program, works by analyzing the amount of tumor that circulates in the patient's blood.
Blood Tests For Detecting Cancer
The use of blood tests for detecting cancer is not new. A liquid biopsy that can detect abnormalities in the blood, for instance, can detect gene mutations present in people with lung cancer. Researchers have also developed a method that analyzes the length of blood telomeres to predict the development of cancer as early as 13 years before diagnosis.
Researchers behind the new technology called CancerLocator, however, think that their test is among the most wide-reaching available with a success rate of 80 percent in detecting breast, liver and lung cancer.
Jasmine Zhou, from the University of California at Los Angeles, said that the program is more accurate at producing a diagnostic result when there is a higher amount of tumor DNAs present in the blood. This means that tumors in well-circulated organs such as the lungs and the liver are easier to diagnose early using this method.
The program works by searching for a particular molecular pattern in cancer DNA in the patients' blood and then comparing the patterns against a database of tumor markers that the researchers collated. DNA from tumor cells end up in the bloodstream during the earliest stages of cancer so they provide a unique target that can help in the early detection of the disease.
For the study published in the journal Genome Biology, the researchers used the computer program and two other methods to test blood samples taken from cancer patients, 29 of whom had liver cancer, 12 had lung cancer, and 5 had breast cancer. The two methods had an error rate of 0.646 and 0.604 but the new program got a lower error rate of just 0.265.
Of the 29 liver cancer patients, 25 had early stage cancer. Of the 12 lung cancer patients, five also had early stage cancer. CancerLocator was able to detect the disease in 80 percent of the cases despite that the level of tumor DNA in the blood is far lower during the early stage, showing the potentials of the methods for cancer diagnosis.
"CancerLocator simultaneously infers the proportions and the tissue-of-origin of tumor-derived cell-free DNA in a blood sample using genome-wide DNA methylation data," the researchers wrote in their study.
"CancerLocator outperforms two established multi-class classification methods on simulations and real data, even with the low proportion of tumor-derived DNA in the cell-free DNA scenarios."
The study, however, involved only three cancer types because of the limited number of blood samples.
Non-Invasive Test For Cancer
Zhou noted the importance of non-invasive methods of cancer diagnosis because the earlier a cancer is detected and caught, the higher chances a person has of defeating the disease.
"We have developed a computer-driven test that can detect cancer, and also identify the type of cancer, from a single blood sample. The technology is in its infancy and requires further validation, but the potential benefits to patients are huge," Zhou said.