As the number of medically important proteins increases, the impact will be momentous, according to N. Leigh Anderson.
Seventy percent of the decisions made by physicians today are influenced by results of diagnostic tests, according to N. Leigh Anderson, founder of the Plasma Proteome Institute and CEO of SISCAPA Assay Technologies. Imagine the changes that will come about when future diagnostics tests are more accurate, more useful, more economical, and more accessible to healthcare practitioners. For Dr. Anderson, that’s the promise of proteomics, the study of the structure and function of proteins, the principal constituents of the protoplasm of all cells.
In explaining why proteomics is likely to have such a major impact, Dr. Anderson starts with a major difference between the genetic testing common today, and the proteomic testing that is fast coming on the scene. “Most genetic tests are aimed at measuring something that’s constant in a person over his or her entire lifetime. These tests provide information on the probability of something happening, and they can help us understand the basis of various diseases and their potential risks. What’s missing is, a genetic test is not going to tell you what’s happening to you right now.”
He goes on to say that molecular markers, accessible through proteomic testing, do tell what’s happening now. “Defects in proteins underlie most of disease, and that’s because the business end of biology involves proteins. They’re the molecular machines that manage all the chemical reactions in our bodies. It’s proteins that send out signals and provide movement in muscles, and it’s proteins that form a lot of the body’s structures.”
He goes on to say, “If we can learn about how these defects are playing out in individuals, particularly by finding out changes in their numbers and types, there will be a vastly expanded use of proteins in diagnostic tests.”
Since the late 1960s, researchers have had a menu of medically significant proteins to examine. There are currently about 100 different FDA-approved tests for proteins found in blood, and additionally, there are 100 laboratory-developed tests offered by the big reference laboratories such as Mayo, Quest, Labcorp, or Sonic.
“The utility of these proteins,” he states, “has already been proven and we know they have enormous relevance and importance. For example, diagnostically, we determine whether you have had a heart attack according to the presence of a diagnostic heart protein circulating in your blood. Or for another example, the amount of a modified protein called hemoglobin A1c in the blood is extremely important for tracking and treating diabetes.”
Proteins are already such critical measures of what is going on in the body that the business of measuring them is a $10 to $20 billion market a year. However, Dr. Anderson believes that instead of the 200 medically useful tests for proteins now available, there are thousands of additional proteins that may be diagnostically important. Almost none of these have been adequately studied.
This is rapidly changing because the technology and the economics have recently improved. “It’s taken an evolution of almost 20 years to arrive at where we are now,” says Dr. Anderson. “Today we have the ability to analyze blood or spinal fluid samples for thousands of proteins at a time, and the cost structure is such that we can now perform followup testing of new candidate biomarkers in very large numbers of people.”
Dr. Anderson knows that testing many markers in large numbers of people is important for understanding and diagnosing disease. “Even when we have similar genes, the mechanics at the protein level of what is going on moment to moment can be surprisingly variable. This means that if you don’t look for what’s happening in hundreds or preferably thousands of individuals, you don’t find what is reproducibly different in a disease. Up until the last couple of years, this kind of testing was so laborious and expensive that we were only looking at maybe ten to 20 people at a time, and with these small numbers, it’s hard to find reproducible differences resulting in useful diagnostic tests.”
This has changed. With recently available technology, particularly with SISCAPA (Stable Isotope Standards and Capture by Anti-Peptide Antibodies) coupled with mass spectrometry, measurement of diagnostic proteins is both more accurate and less expensive. In the past, when you gave a blood sample to a clinical lab, each measurement was done separately from a different sample of blood. That meant each kind of test resulted in additional cost. However, with the new techniques of mass spectrometry and SISCAPA, you can measure up to 50 proteins in one sample, at a fraction of the cost of doing 50 separate tests.
“We expect that as the number of medically important proteins increases, the impact will be momentous,” he says. “For a start, at the individual level, the new proteomic diagnostics will mean identifying diseases at their earliest and most treatable stage. This should have an enormous impact on both the cost and the effectiveness of healthcare.”
He goes on to talk about how, in the next few years individuals will no longer have to go to the doctor’s office or the hospital for these kinds of tests. Instead, they will be able to collect a few drops of blood dried on a piece of paper in the convenience of their own homes and mail these to a clinical lab for testing. Interactions with their physicians, provided with advance knowledge of the individual’s medical condition, will focus on figuring out what to do about their conditions, as opposed to starting from scratch in trying to diagnose them.
Another improvement is the ability to compare each person’s test results with his or her own normal range, something that up to now has been impractical because of cost and inconvenience. “The normal range for the population as a whole can be quite different from your normal range,” Dr. Anderson points out. “What you want to compare yourself against is your own numbers from the past. A change that is medically significant for you might not be picked up if you’re going by what is normal for the population as a whole.”
The new “dried blood spot” technology has suddenly reduced the problems of cost and inconvenience for frequent testing. “Instead of a trip to the doctor’s or the lab or the hospital, an individual can take a tiny lancet, collect a couple of drops of blood on a filter paper, allow it to air dry, and then mail it to a lab. With this technology, we can derive more medical information than we could in the past from many vials of an individual’s blood.”
This kind of information is particularly well-adapted to the new informational structures, such as iPads or mobile phones. “It means people can become much more knowledgeable and sophisticated about managing their own health.”
The mass spectrometry technologies together with SISCAPA are fixing the quality issues. Lowering the cost structure is making it possible to do many tests at once. And finally, the dried blood spots technology is enabling the collection of longitudinal samples over time.
“It’s been a long time coming,” Dr. Anderson summarizes, “but in the last year or so the technological corner has been turned, and prospects for improvements in diagnostic proteomics rival the advances we’ve seen in genomics in the last ten years.”
For more on how proteomics is having an impact on diagnostics, be sure to check out the video “A Test In Focus—Thyroglobulin Mass Spectrometry, Serum“.
Mitzi Perdue, GEN’s corresponding editor, holds degrees from Harvard and George Washington University. She has authored more than 1,600 newspaper and magazine articles on science R&D and clinical medical applications, as well as on food, agriculture, and the environment. Perdue has a strong understanding of complex scientific and mathematical concepts. For 22 years, she was a syndicated columnist for the Scripps Howard News Service and before that, California’s Capitol News. Perdue is also the author of the newsletter from the professional association, Academy of Women’s Health. She has produced and hosted more than 400 interview shows, often in conjunction with scientists at the University of California at Davis. She is a former Commissioner for the U.S. National Commission on Libraries and Information Science and a former Trustee for the National Health Museum.
This article was originally published in the June 12 issue of Clinical OMICs. For more content like this and details on how to get a free subscription to this new digital publication, go to www.clinicalomics.com.