Scientists around the world trying to find a way to identify cancers before they become deadly. Still a work in progress, but judging by the results of a recent study, we’re one step closer to solving this puzzle. A special blood test can detect fragments of mutated DNA in the early stages when the tumor is still impossible to detect by any of the existing devices.
The results of the study were presented at the annual conference of the American society of clinical Oncology (American Society of Clinical Oncology). According to the presented data, 73% of mutations found in the tumors of 124 cancer patients, was also detected in DNA fragments, moving freely in the bloodstream.
A new diagnostic method was developed by GRAIL located in San Francisco, “daughter of” genetic giant Illumina. For detection of the mutated fragments, the scientists used “high-intensity” sequencing, suggesting interesting parts of the genome will be read on average 60 thousand times with the aim of increasing accuracy. GRAIL intends to use the new method in the study, which will be attended by 10 thousand Americans — people with cancer, and those with no cancer diagnosis.
“The discovery of a direct relationship between the diagnosed tumors and circulating in the bloodstream by the fragments of the mutated DNA is an important first step, long way to creation of approaches that will allow you to use the blood test to determine who has cancer, and someone — no, — said the head of clinical development: Dr. mark Lee (Mark Lee).
As the name implies, the company developing blood test that could detect cancer earlier than it will appear on x-rays is the Holy Grail of modern oncoprophylaxis. Theoretically, if the doctors will be able to detect the tumor early enough and determine how aggressive doctors can prescribe treatment is much more effective, while choosing the optimal drug and treatment of an ever-expanding Arsenal of methods of struggle with cancer. The latest developments in this area belong to the category of immunotherapy, drugs that cause an immune system of the patient to destroy the tumor or at least restrain their growth.
According to experts of company GRAIL, they have developed ultra-sensitive detection method of cancer generates about 100 times more data than conventional screening tests.
Examination of one patient leads to approximately 1 terabyte of data.
In recent years, the technology of genome sequencing has moved far ahead, as well as data processing methods, which led to the emergence of so-called “liquid biopsy”. The fact that all the cells in the process of life and release into the surrounding extracellular space fragments of DNA. And tumor cells — is no exception. But there is one problem — almost all “cell-free” DNA, circulating in blood, “dropped” from normal healthy cells. The share of “cancer” DNA accounts for only one tenth of one percent. This means that diagnostic tests based on “liquid biopsies” should be very, very accurate when it comes to detecting specific mutations, indicating the presence of cancer.
GRAIL is not the first company engaged in the development of tests based on “liquid biopsies.” Doctors have today sent blood samples of their patients to laboratory specialists studied the DNA of the tumor. These studies help doctors determine which targeted drugs it is better to assign, they provide information about stages of the disease and early relapse. However, the very diagnosis of cancer based on the blood test still loomed somewhere on the horizon of the possible.
The fundamental difference between the approach of the GRAIL, lies in the fact that the company uses the data of a large-scale clinical trials. Only after analyzing thousands of samples can be set, which means the emergence of a particular tumor-associated DNA fragment in the bloodstream. If the patient has a tumor? Will it be a problem and, if so, how fast? The creators of the new test hope that over time their offspring will be able to give answers to all these questions.