One of the main challenges in the fight against cancer is early detection. When a tumor is located in an organ, the chances of long-term survival are multiplied. However, the need for invasive tests to detect many types of cancer, their cost, and the risk of generating false positives mean there is still a lot of room for improvement. One of the alternatives that have been developed in recent years are liquid biopsies, a type of blood test that allows the detection of tumor DNA released into the bloodstream by tumors that are still invisible.
However, these tests only achieve a sensitivity of around 10% in the earliest phase of cancer, when it has not left the organ of origin, and there are tumors such as brain tumors that escape these tests. Also, some types of cancer do not release detectable levels of DNA. A recent study estimated that some 12 types of tumors produce an adequate signal, but leave 30 of the most frequent, which cause 50% of the cases and a third of the deaths from cancer in the world, outside the scope of these tests. Finally, there are doubts about the true prognosis of tumors detected by current liquid biopsies, leaving the possibility that these tests produce unnecessary diagnoses that do more harm than good. To combat this last weakness, one of the measures used has been the combination of tests.
Today, Magazine PNAS publishes the results of a study testing the potential of a new class of biomarkers that could improve the chances that various types of cancer can be detected at an early stage in the near future with just a blood or urine test . In a proof of concept, urine and blood plasma samples from 1,260 volunteers were used to analyze the levels of glycosaminoglycans, molecules that can be related to the presence of 14 types of cancer.
As the authors explain, this method was able to raise the sensitivity to tumors in its first phase from the previous 10% to 62%. In addition, it made it possible to predict the location of the tumors with an accuracy of 89%. Another factor highlighted in the article about the new method is that it would cost around $50 per test, between five and ten times less than those that look for tumor DNA circulating in the blood, as liquid biopsies now do.
Francesco Gatto, a researcher at the Karolinska Institute (Sweden) and lead author of the study, explains that there are still steps to be taken for this type of test to reach routine medical practice. “The next step is to confirm it in a sample of more than 10,000 participants to see the setting in which it would make the most sense to use it and before being approved for the detection of many types of cancer, larger studies would be necessary, with 100,000 participants,” says Gatto. The researcher believes that this type of test would make more sense in people “with a high risk of cancer, someone who is over 55 years old or with a family history of cancer.” Finally, the researcher believes that these analyzes could be combined with those that look for DNA. “The same blood sample could be used to test for glycosaminoglycans and genomic markers. […] The combined capacity could be enough to become a unique screening system”, he concludes.
To bring this type of liquid biopsy to the market to detect various types of cancer at an early stage, in 2017, Gatto founded together with Jens Nielsen, who also signs this work in PNASthe company elypta. That company achieved €21 million in a financing round last June to commercialize this type of test. If these biopsies end up fulfilling what they promise, cancer mortality could be reduced by up to 15%, according to a study Prepared by a team from the Grail company, which also develops this type of test.
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