An innovative, simple blood test that can diagnose a variety of diseases, including cancer, has been developed by researchers at the Technion-Israel Institute of Technology.
Professor Aryeh Admon of the biology faculty claims that the test will provide doctors with a rich variety of information that until now has not been available and is suited to the trend of “personalized medicine,” in which treatment is matched to the genetic and other characteristics of the patient. The development was part of the doctoral work of Dr. Miochal Bassani-Sternberg and will help fit medication to the patient.
As opposed to current blood tests for cancer which merely note whether cancerous cells are still in the blood stream, the new test will be able to differentiate between different kinds of cancers and tumors as well as other diseases. Scientists are now working on the technique.
Admon said it was known that when the proteins in a cell deteriorate, they are broken down into their building blocks of amino acids to create new proteins. Some of the products of this process, however, are not completely broken down and remain as pieces of short proteins called peptides.
Meanwhile, some of these peptides are displayed on the surface of the cells with help from the human leukocyte antigen (HLA) protein. When the peptides from the proteins of the disease “report” their state of health to the immune system, the immune cells kill the sick cells and prevent the spread of the disease.
The body-cells not only present the HLA protein on their surfaces but also release part of these protein molecules into the bloodstream with the characteristic peptides. Cancer cells release larger amounts of the HLA protein with the peptides into the blood in an effort to “confuse” the immune system, explained Admon. Thus, the two Technion researchers reached the conclusion that by characterizing the variety of peptides linked to the HLA proteins that were released into the blood, they could diagnose cancer and other disorders.
The researchers separated the HLA proteins from the other blood proteins and then released the linked peptides. Using a mass spectrometer device, they succeeded in identifying the sequence of amino acids of the separated peptides and the original proteins that were in the cells in which the peptides were produced.
In one blood sample, thousands of different peptides can be identified, providing vital information about the disease or the tumor. There are peptides that are not present in healthy people, and when they are found, the patient can be sent for additional tests, the researchers said.
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