Posted on Mar 07, 2017, 6 a.m.
Bioengineers have developed a new blood test that can detect cancer early, as well as identify where it is growing in the body.
A recent breakthrough appears to have made it much easier to detect cancer and pinpoint its exact location. The advances were made by University of California at San Diego bioengineers. The research team created a blood test that identifies cancer and pinpoints its exact location in the body. Information about the new blood test was published in the March 6 edition of Nature Genetics.
About Cancerous Tumors
As a cancerous tumor progresses, it takes over parts of the body. It battles “regular” cells for space as well as nutrients. The tumor kills these cells. Upon death, such cells release DNA in the blood. This DNA impacts the affected tissue.
The Test's Importance
The team's blood test will ameliorate efforts to diagnose cancer in a timely manner. When cancer is identified early, there is a drastically reduced chance that an invasive surgical procedure will have to be performed. The test involves a filtering of DNA released by tumor cells that are perishing. The tests detect signs of tumor DNA within the blood of those afflicted by cancer. The typical blood test does not specify tumor location. The UCSD research team has made considerable progress in this challenge. The team, led by the study's senior author Kun Zhang, has discovered a clue within blood, that identifies tumor cell position. Pinpointing the location makes it possible to identify cancer as early as possible.
Zhang's research team figured out how to make use of a method that screens for a specific DNA signature known as CpG methylation haplotypes. These are the methyl groups to nearby CG sequences within a DNA molecule. The specific tissues within the body are identified according to the idiosyncratic signature of the methylaton haplotypes. Zhang's team noticed signals from other cells and figured integrating the sets of signals with one another would determine whether a tumor is present and if so, where it is located.
The Roots of the Test
The researchers assembled a database of complete CpG methylation patterns. They used 10 different regular tissues and blood samples from cancer patients to create a database of genetic markers that are unique to cancer. Zhang's group screened blood samples for signs of cancer markers and methylation patterns in specific tissues. The test functions similar to a dual authentication process as the combination of each type of signal higher than a statistical cutoff is necessary for a positive match.
"Identification of methylation haplotype blocks aids in deconvolution of heterogeneous tissue samples and tumor tissue-of-origin mapping from plasma DNA," Nature Genetics (2017).DOI: 10.1038/ng.3805