Blood test for early detection of cancer through DNA


This test enabled a team of scientists from the United States, the Netherlands and Denmark to accurately identify avoiding ‘false positive’ results, more than half of a sample withdrawn from 138 people with colorectal, breast, lung and Ovary at an early stage of the disease.

The researchers say this test is novel in distinguishing between blood cell changes between DNA (genetic material) from cancer cells and other genetic mutations that can sometimes be confused as cancer biomarkers.

According to the researchers, people who could benefit most from a blood test of this type would be smokers, since they are at increased risk of having lung cancer, as well as women with hereditary genetic mutations that are at the origin of breast cancers and of the ovary.

“This study shows that early identification of cancer using DNA changes in the blood is feasible and that our high-precision DNA sequencing method is a promising approach”, said one of the scientists, Victor Velculescu, who is also a professor of oncology and pathology at the Johns Hopkins Center for Cancer in the United States, quoted in a statement by Johns Hopkins Medicine, a US health care institution.

To create this new blood test, Victor Velculescu and the other team used a kind of genomic sequencing (genetic information sequencing) that enables targeted DNA correction.

This sequencing method allows 30,000 times to decode each chemical code in the DNA. For the study, the scientists collected blood and tumor tissue samples from 138 colorectal, breast, lung and ovary cancer patients at all stages of the disease.

They subsequently searched the blood for mutations in 58 genes associated with various types of cancer. In all, they were able to detect 86 of a total of 138 cancers in stages I and II (early stages).

And, the researchers also performed genomic sequencing of tumors from 100 of the nearly 200 patients tested (altogether) and found that 82 of these patients had genetic mutations related to DNA changes detected in the blood.

Although the results are promising, the blood test, which can be used on healthy people, has to be validated with a larger number of people, says the team.

In none of the blood samples from 44 healthy subjects tested was any genetic mutation derived from cancer cells detected.