Cancer by a drop of blood
Pancreatic cancer is a widespread disease with a high mortality rate. Its treatment is complicated by the fact that it is usually detected in the late stages. A new diagnostic test developed by researchers at the University of California, San Diego, will help detect the disease earlier.
The test is based on the detection of nanoscale biological structures in the blood – exosomes. These vesicles are secreted by all cells of the body, including cancer cells, they contain proteins and genetic material that can serve as biomarkers of cancer.
Previously, it took a long time to isolate exosomes in the blood. It was necessary to pretreat or destroy the blood cells, as the vesicles are very small and fragile. The new test uses electronic chips to extract exosomes directly from the blood in minutes. A drop of blood is sufficient for analysis without any pretreatment.
The chip performing the analysis is powered by an alternating current source. It selectively takes nanoscale particles, including exosomes, from the blood and collects them with small electrodes on its surface. Larger particles are washed out, while smaller ones remain. Then fluorescein-labeled antibodies are added, which specifically target two biomarkers of pancreatic cancer: glipican-1 and CD63. If these proteins are present in the blood, bright spots appear noticeable under the microscope. The whole process takes less than an hour.
A drawing from an article in ACS Nano.
The test was tested in a study with a small sample – 31 blood samples, of which 20 belonged to patients with pancreatic cancer, 11 to healthy volunteers. The test demonstrated 99% sensitivity and 82% specificity.
The main task of the test is to detect cancer at the earliest stages. The authors are working to increase the sensitivity of the test so that it is able to detect the disease at stage 0-1.
The group is planning a larger study involving patients with risk factors for pancreatic cancer: newly diagnosed diabetes, burdened by heredity, obesity and bad habits. They will be monitored for a long time, periodically performing a blood test using a new test. Some of them are subsequently diagnosed with cancer, after evaluating the results of their tests throughout the study, it will be possible to see how early the test is able to detect biomarkers in the blood.
Researchers are also studying other biomarkers in the blood besides glypican-1 and CD63 to improve the accuracy and sensitivity of this system to detect pancreatic cancer.
Article by J. M. Lewis et al. An Integrated Analysis of Exosomal Protein Biomarkers on Alternating Current Electrokinetic Chips Enables Rapid Detection of Pancreatic Cancer in Patient Blood is published in the journal ACS Nano.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru Based on the materials of the UC San Diego News Center: New Blood Test Rapidly Detects Signs of Pancreatic Cancer.