The Genetic Signature Of Diseases: The Future Of Diagnostics

Most of the DNA genomic sequences of organisms are now known, however those of some organisms continue to be the focus of ongoing scientific research throughout the world. It is widely accepted that certain genetic variations have a close link to the likelihood that an individual will be affected by a disease such as cancer, or that particular drugs will be effective in treatment. The clinical value of genetic tests based upon genetic markers remains speculative, and the utility of such tests is limited to the estimation of risk of disease and of the efficacy of therapeutics. There is an important additional benefit of recent advances in genomics that may not have received comparable attention recently: detection of diseases that may already exist in the body, based upon our knowledge of specific genetic markers. In addition to advances in human genomics, great strides have been made in the discovery of specific genetic markers linked with tumor development, infectious diseases such as mycobacterium tuberculosis, markers of well defined fetal anomalies like Tay-Sachs Disease and Fragile X Syndrome. In some instances, it may be important to determine specific tissue genetic markers, even those from a transplant donor, in order to distinguish donor from recipient cells or tissue. In general, it is now possible to define, with great precision, specific genetic markers that then can be used to find foreign biological material that may be inside the body. Translated into simple terms, it is now possible to detect almost any genetically distinct “alien” biological material in the body, and to do so quickly and safely to permit early, more effective treatment, and to facilitate monitoring of a patient's progress. Until recently, it has been tacitly assumed that this kind of molecular diagnostics was limited to the use of specimens such as blood, sputum or biopsy, all of which have numerous drawbacks beyond the simple fact that each can represent a serious hazard. An important recent discovery found that nucleic acid markers present in blood circulation pass through the kidneys and are readily detectable in urine. This discovery shows that kidneys perform the most important and costly steps in isolating genetic markers from the blood stream, and that the markers are efficiently collected in a simple milieu of urine. The scientists at Xenomics (XNOM.OB) were the first to ask whether DNA from cells throughout the body can appear in urine. It was generally taught by scientists and clinicians that DNA was simply too large and had the wrong electronic charge to get through the kidney's filtration apparatus. Based on their work on apoptosis forover two decades, Xenomics' scientists were well aware of the fact that over one hundred billion cells normally die each day by this process. Along with many cellular components such proteins and lipids, genomic DNA is disposed of by breaking the very large molecules into small, uniform segments of about 180 base pairs during apoptosis[1]. These DNA segments are known as nucleosomes, and can be detected in plasma. Until the team of Xenomics scientists made this discovery, scientists were unaware that these DNA segments passed through the kidney barrier and could be found in urine. This newly found DNA was called “transrenal DNA,” or tr-DNA for short, and was the basis for a truly counterintuitive discovery. Because of this, Xenomics received the first United States Patent on the diagnostic use of these soluble DNA fragments in urine. It has been proven in laboratory experiments and clinical studies on tr-DNA that genetic signatures in urine specimens can be detected for viruses such as HIV, bacteria such as those that cause tuberculosis, parasites such as those responsible for malaria, and DNA signatures that arise from tumors and even a developing fetus in utero. The data is obtained in a growing number of labs in different countries and has been published in peer-reviewed papers in the medical literature. These include laboratories at Drexel University in collaboration with the University of Michigan Medical Center, Friedrich-Schiller-University in Germany, Showa University School of Medicine in Japan, and The University College of London to name just a few. It is especially interesting to note that the genetic signatures of foreign material in the body is not to be found in the sediment of urine, the source of all current urine DNA diagnostic material, but rather in the soluble portion of urine, the portion of each specimen that is currently discarded by laboratories when they attempt to detect DNA markers. The discovery of tr-DNA provides a new outlook for the future of molecular diagnostics, one that is expected to have great influence on the way medicine is practiced in the future. Instead of traditional reliance upon blood specimens, tissue biopsies, and other tests, a simple, safe urine specimen can be collected and analyzed using the most sensitive technologies available today. Currently the Polymerase Chain Reaction, known as PCR, is the most common technique used today in genomic studies. PCR is also used in tr-DNA based tests to amplify and detect specific DNA markers for molecular diagnostics. Even more useful and sensitive technologies are expected to emerge in the next few years, base on the work being done at many research laboratories worldwide, technologies that can then be applied to the tr-DNA analysis. Furthermore, clinics will be able to reduce exposure to hazardous biological specimens, making the clinic environment safer for both patients and healthcare workers, since urine is safe whereas blood and tissue are not. Testing laboratories will now be able to run a broad array of molecular diagnostic tests on small urine specimens, using a single platform. Tr-DNA tests can be significantly less expensive to run than either blood or tissue, which require costly manipulation to extract and identify DNA markers. Thus, tr-DNA tests represent another leap forward based on the fact that DNA from a single urine specimen can be used to perform many tests for multiple disease targets simultaneously, by simply altering a single component reagent known as the primer (or probe) to detect markers of very different diseases. Physicians can now take a simple urine specimen from a cancer patient, and it will provide direct evidence that a particular genetic tumor marker is present in the body. Urine specimens can now be used to monitor a patient's therapy, be it for cancer or an infectious disease such as tuberculosis. In the near future, researchers will continue to discover and validate new genetic markers of diseases and disease-causing agents. New, specific genotypes of tumors or viruses and bacteria will be discovered, giving an ever-sharpening focus to attempts to not only detect diseases, but also more accurately define the patient's prognosis and response to drugs. New genetic forms of infectious disease agents are emerging in the USA and worldwide, that are more virulent and often resistant to conventional therapies. These may be detectable in one basic tr-DNA diagnostic test such as for Mycobacterium tuberculosis or HIV Proviral DNA. Similar advances are expected in the field of cancer detection and treatment. The detection of tr-DNA is clearly the only completely safe, non-invasive means to obtain access to the genetic information from foreign material in the body. Xenomics intends to make an array of tr-DNA tests available commercially in the coming year. [1] Apoptosis is also known as Genetically Programmed Cell Death, the normal process where cells in the body are safely removed andreplaced with new cells. By L. David Tomei, Ph.D. CEO and founder, Xenomics Inc. New York, N.Y. "Source - www.medicalnewstoday.com":[http://www.medicalnewstoday.com/medicalnews.php?newsid=53024&nfid=crss]

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