Liquid Biopsy, one of the hottest words recently, has been selected as on of the 2015 Top Ten Breakthrough Technology by MIT Technology Review. Years before, it’s only limited to researches, but now it is more frequently used in clinical.
Liquid Biopsy, in fact, is to determine the human blood floating DNA fragments using high-speed sequencing. When a person’s body has exogenous DNA, such as infants, cancer or organ transplant, this test can provide information. Liquid biopsy allows scientists to locate, research and monitor those interlopers only by exsanguination, and its applications are rapidly expanding.
In a summary, there exists eight major applications of liquid biopsy. In this part, the first four applications would be introduced and the last four would be listed in the next post.
Down syndrome
So far, the main commercial application of liquid biopsy is during pregnancy. Starting from 2011, some companies have launched a “non-invasive prenatal testing (NIPT), detecting Down Syndrome by analyzing the mother’s blood. The test typically is to count DNA fragments to determine whether the fetus has too much or less chromosomes. Because Down Syndrome is caused by extra copy of chromosome 21.
Rare birth defects
NIPT can not only reveal the information of extra chromosome, but can also allow you to understand the fetal genome. They can locate the missing piece of DNA, that is to say microdeletion, which would cause rare diseases, such as cri-du-chat syndrome. Some companies have already or will soon begin providing microdeletion diseases detection. However, since these diseases are very rare, there exists a high false positive rate.
Even so, getting more information from the fetal DNA seems to be the trend. Researchers in Stanford have found that they can sequence the fatal complete genome in the mother’s blood. Currently, another research direction of the liquid biopsy is how to find differences in DNA and single base mutation, which caused the single-gene disorders such as cystic fibrosis and thalassemia.
Sexing
If you are pregnant and your blood has Y chromosome fragment, then it is a boy. On the contrary, it’s a girl. Sexing is one of the easiest applications of liquid biopsy. But sexing is inhibited in some countries like China. Currently, some companies have begun to sell related kits.
Paternity
Some companies provide a kind of liquid biopsy that can determine the father of the fetus. The test can be performed at nine weeks of pregnancy at a cost of $795. While, previously, paternity test has to wait until 15 weeks of pregnancy. However, testing may also be required to provide the blood samples of all possible fathers.
To be continued…