Possible Genetic ‘Switches’ for Blood Sugar Control Detected

But applications for diabetes years away, researchers say.

TUESDAY, Nov. 2 (HealthDay News) — A new genetic analysis has uncovered specific regions in the DNA of certain human pancreatic cells that appear central to the regulation of insulin and other functions of the pancreas.

The new effort — conducted by researchers at the National Human Genome Research Institute (NHGRI) — takes scientists a step closer towards understanding the complex genetic underpinnings of insulin deficiency and the onset of type 2 diabetes, which accounts for most of the 23 million cases of diabetes among Americans and the more than 170 million cases worldwide.

By honing in on clusters of hormone-producing pancreatic cells known as islets, the investigators were able to detect about 18,000 “molecular on-off switches” (or so-called “promoters”) that control gene behavior. Several hundred of these gene-adjacent switches were previously unknown.

In a U.S. National Institutes of Health (NIH) news release, study co-author Michael Stitzel explained that previous gene-mapping work has pointed out some genetic differences between type 2 diabetic and non-diabetic individuals in specific regions of the genome.

“But substantial efforts are required to understand how these differences contribute to disease,” he said. “Defining regulatory elements in human islets is a critical first step to understanding the molecular and biological effects for some of the genetic variants statistically associated with type 2 diabetes.”

Stitzel and colleagues from the NIH Intramural Sequencing Center, Duke University in Durham, N.C., and the University of Michigan in Ann Arbor report their findings in the Nov. 3 issue of Cell Metabolism.

The new work has also enabled the authors to identify another 34,000 regulatory “modules” located slightly farther away (than the 18,000 on-off switches) from the genes they control. They believe that these distinct “regulatory elements” may be critical to proper blood glucose levels.

Upwards of 50 genetic abnormalities believed to have an association with islet-related pancreatic dysfunction were also uncovered.

“These findings represent important strides that were not possible just five years ago, but that are now realized with advances in genome sequencing technologies,” Dr. Eric D. Green, NHGRI director, noted in the NIH news release.

“Very exciting” is how Dr. Stuart Weiss, an endocrinologist at New York University Medical Center and a clinical assistant professor at the NYU School of Medicine in New York City, described the current effort.

“It’s clearly the future of medicine,” he said. “However, the fact of the matter is that all sorts of factors are involved in the development of diabetes, and different people require different treatments. And just when you think that you understand it, another curve comes at you. So it’s very difficult to think that we’re going to find a magic bullet. And I would think that the clinical applications from any of this are probably years and years away.”

More information

For more on genetics and diabetes, visit the American Diabetes Association.

SOURCES: U.S. National Institutes of Health, news release, Nov. 2, 2010; Stuart Weiss, M.D., endocrinologist, clinical assistant professor, NYU School of Medicine, New York City

Copyright © 2010 HealthDay. All rights reserved.

DNAWellnessinfo.com Resource:  http://www.doctorslounge.com/index.php/news/hd/15338

TGen-Mayo Clinic study discovers role of DNA methylation in multiple myeloma blood cancer

Science Centric | 1 October 2010 11:18 GMT

DNA methylation – a modification of DNA linked to gene regulation – is altered with increasing severity in a blood cancer called multiple myeloma, according to a study by Mayo Clinic and the Translational Genomics Research Institute (TGen).

And at specific points of DNA, ‘global hypomethylation,’ in which many genes lose the modification, may be associated with the step-by-step development of myeloma, according to a scientific paper published this month in the journal Cancer Research.

‘This is the first study to show that hypomethylation occurs early in the development of multiple myeloma and increases through disease progression,’ said Dr Bodour Salhia, a TGen cancer researcher and the paper’s lead author.

DNA methylation suppresses the expression of viral genes and other harmful elements incorporated over time into an individual’s genome. In cancer, hypermethylation at certain genomic locations can turn tumour suppressing genes off, while hypomethylation in some instances may lead to the over-expression of oncogenes, or those genes that give rise to cancer, and is linked to chromosomal instability.

However, there is still much to learn about the consequences of altered methylation.

In this study, researchers examined the methylation status of more than 1,500 CpGs. This is shorthand for C-phosphate-G, or cytosine and guanine – two of the four chemicals that comprise DNA – separated by a phosphate group, which links the two nucleosides together.

Researchers used a high-throughput universal bead array technology to examine CpG methylation at different stages of multiple myeloma, evaluating DNA methylation events associated with the progression of tumours.

They performed DNA methylation profiling analysis for more than 800 genes, including tumour suppressors, oncogenes, and genes involved in cancer-related cellular processes. This process contrasts with previous studies that focused on the analysis of a single gene.

They found only a few genes that were hypermethylated, but importantly found many more hypomethylated genes, even in the earliest stages of multiple myeloma.

‘Our data suggest that the overall degree of methylation may have some prognostic value, and further studies are needed to determine the functional and clinical significance of our findings,’ said Dr John Carpten, Director of TGen’s Integrated Cancer Genomics Division and the paper’s senior author.

Dr Salhia, added, ‘This study represents the most comprehensive examination to date of the role of methylation in multiple myeloma, and is expected to lead to an improved understanding of the biological mechanisms involved in the development of this type of cancer.’

The study of DNA methylation falls under epigenetics – an emerging field in cancer research. Unlike the study of genetics, epigenetics refers to the study of gene activity that does not involve hardwiring alterations in the genetic code. These epigenetic events, which lay atop the genome, are an intricate and heritable mechanism of regulating the expression of genes.

‘Understanding the full spectrum of epigenetic modifications will be key to improving the clinical management of the disease, and studies should continue to find new ways of treating multiple myeloma by targeting the multiple myeloma epigenome. This study also emphasises that hypomethylating strategies may not be the next necessary steps in drug development.’ said Rafael Fonseca, M.D., Deputy Director of Mayo Clinic Cancer Centre in Arizona.

Source: TGen

DNAWellnessnessinfo.com Resource:  http://www.sciencecentric.com/news/10100122-tgen-mayo-clinic-study-discovers-role-dna-methylation-multiple-myeloma-blood-cancer.html

ADHD Genetic Link: Is Attention Deficit All in the Genes?

October 1, 2010 8:51 AM  -  cbsnews.com
Posted by David W Freeman

CBS) What causes attention-deficit hyperactivity disorder, or ADHD?

A new study points the finger not at bad parenting or too much sugar in the diet but at heredity.

Scientists at Cardiff University in Wales compared the DNA of 366 children with ADHD to that of 1,047 kids without the condition. They found that kids with ADHD were more likely to have small segments of DNA that were duplicates or missing.

“We hope that these findings will help overcome the stigma associated with ADHD,” Professor Anita Thapar, the study’s lead author, said in a written statement. “Too often, people dismiss ADHD as being down to bad parenting or poor diet. As a clinician, it was clear to me that this was unlikely to be the case. Now we can say with confidence that ADHD is a genetic disease and that the brains of children with this condition develop differently to those of other children.”

The study was published online in The Lancet, the English medical journal.

Worldwide, about one in 50 children have ADHD. The condition – which makes kids restless, impulsive, and easily distracted – is incurable but can often be controlled with medication and therapy.

DNAWellnessinfo.com Resource: http://www.cbsnews.com/8301-504763_162-20018239-10391704.html

Cancer treatment found among junk DNA

September 27, 2010

AAP

Australian scientists have found a new and potent way to fight cancer among what was once thought of as junk DNA.

The experimental technique, proven to shrink tumours in mice, involves “microRNA”.

Dr Alex Swarbrick said this new class of genes was until recently considered to be junk DNA, the term used to describe the bulk of information contained in the genome that has no apparent purpose.

But far from being junk, he said one specific type of microRNA (microRNA 380) has been found to play a pivotal role in allowing certain types of cancer to grow.

Dr Swarbrick and his research colleagues also found that blocking the action of this microRNA in mice with neuroblastoma cancers caused their tumours to shrink.

“The revolutionary thing about this finding is that it’s the first time anyone has blocked the growth of a primary tumour by the simple delivery of a microRNA inhibitor…,” Dr Swarbrick, from Sydney’s Garvan Institute of Medical Research, said.

“That, of course, makes this microRNA a potential therapeutic target for all cancers that depend on it.”

The discovery points to a new way to combat cancer that could be as simple as a twice-weekly injection of a microRNA inhibitor.

MicroRNA 380 has its cancer-promoting effect on the body by disabling another gene (P53), which is known as the “guardian of the genome” because of its role in suppressing tumour growth.

Dr Swarbrick said the studies in mice showed how their P53 gene was disabled by “overproducing” microRNA 380.

He said this microRNA served a necessary purpose in embryos when cells needed to divide quickly and it should play no role in a “normal adult’s cells”.

It was not yet known why it could become active and with cancer-causing effects later in life.

“By blocking it, you’re effectively returning cells to normal,” Dr Swarbrick said.

“We still don’t know why it gets switched on again in certain cancers.

“(However) understanding that certain cancers appear to be regulated like this gives us a new avenue to explore in their treatment.”

Dr Swarbrick said the technique could also be applied to treat brain tumours as well as melanoma, which are known to be caused by a disabled P53 gene.

The research was conducted along with Brisbane-based Dr Susan Woods from the Queensland Institute of Medical Research, and a colleague in the US.

The results are reported in the journal Nature Medicine on Monday.

© 2010 AAP

DNAWellnessinfo.com Resource:  http://news.smh.com.au/breaking-news-national/cancer-treatment-found-among-junk-dna-20100927-15sv8.html

DNA Swap Between Eggs May Curb Inherited Disorders, Study Finds

April 14, 2010, 4:59 PM EDT  BusinessWeek

By Kristen Hallam

April 14 (Bloomberg) — Scientists discovered a way to transfer DNA from one fertilized human egg to another in a pioneering effort to avert the spread of a host of genetic disorders such as learning disabilities and diabetes.

The researchers at Newcastle University in northern England extracted the genetic material contributed by the egg and sperm and implanted it into a donor egg, according to the study published today by the journal Nature. It’s the first time DNA has been transferred between two fertilized human eggs.

The approach discards almost all the defective DNA inherited from the mother that disrupts the tiny energy generators inside cells, and may prevent related disorders such as blindness and liver failure, the researchers said. They are planning further experiments to see whether the technique could help people who carry mutated genes to have healthy babies — an end result that may still be a decade away.

“We have no way of curing these diseases at the moment, but this technique could allow us to prevent the diseases occurring in the first place,” said Doug Turnbull, the lead researcher and a professor at the university’s medical school, in a statement. “It is important that we do all we can to help these families and give them the chance to have healthy children, something most of us take for granted.”

Parents contribute a total of 23,000 genes to a child. In a fertilized egg, this genetic material is housed in two pronuclei, one from the egg and one from the sperm. The egg also contains mitochondria, tiny structures found in every cell that produce the chemical fuel needed for life. Mutations in the mitochondrial DNA, which are passed on from the mother, can disrupt the functioning of these energy generators.

‘Changing the Batteries’

The Newcastle scientists were able to extract both pronuclei and implant the material that makes each child unique into a donor egg with healthy mitochondria. They created 80 fertilized eggs using the technique and grew them in a laboratory for six to eight days. That showed for the first time that eggs produced in this way could reach the stage at which they each had divided into about 100 cells.

“It’s like changing the batteries,” Turnbull said today at a news conference in London. “These are diseases where there is battery failure. Because mitochondria are everywhere, these diseases can affect all parts of the body. None of my patients is exactly the same.”

About 1 out of every 200 children is born each year with mutations in mitochondrial DNA that cause no symptoms or only mild conditions. One in every 6,500 children is born with a more serious mitochondrial disease, ranging from muscular weakness to fatal heart failure. Some disorders lead to death in early infancy.

The research was funded by the Muscular Dystrophy Campaign, the U.K. Medical Research Council and the London-based Wellcome Trust, the world’s second-biggest medical research charity.

–Editors: Phil Serafino, Angela Cullen

To contact the reporter on this story: Kristen Hallam in London at khallam@bloomberg.net

To contact the editor responsible for this story: Phil Serafino at pserafino@bloomberg.net

DNAWellnessinfo.com Resource:  http://www.businessweek.com/news/2010-04-14/dna-swap-between-eggs-may-curb-inherited-disorders-study-finds.html

Key protein aids in DNA repair

April 11, 2010- physorg.com

Scientists have shown in multiple contexts that DNA damage over our lifetimes is a key mechanism behind the development of cancer and other age-related diseases. Not everyone gets these diseases, because the body has multiple mechanisms for repairing the damage caused to DNA by aging, the environment and other human behaviors – but the mechanisms behind certain kinds of DNA repair have not been well-understood.

In a paper published today in the journal Nature, researchers at the University of North Carolina at Chapel Hill’s Lineberger Comprehensive Cancer Center have shown that a particular protein – called Ku – is particularly adept at healing damaged strands of DNA.

According to Dale Ramsden, PhD, associate professor in the department of biochemistry and biophysics and a member of the curriculum in genetics and molecular biology, Ku is a very exciting protein because it employs a unique mechanism to repair a particularly drastic form of DNA damage.

“Damage to DNA in the form of a broken chromosome, or double strand break, can be very difficult to repair – it is not a clean break and areas along the strand may be damaged at the level of the fundamental building blocks of DNA – called nucleotides,” he notes.

Broken chromosomes can be compared to a break in a strand of yarn made up of several different threads or plies. Unless scissors are used to cut the yarn, the strand frays and may break or be damaged at several different places up and down the length of the yarn. These rough ends get “dirty” – making them harder to repair.

Provided by University of North Carolina

DNAWellnessinfo.com Resource:  http://www.physorg.com/news190207556.html

Disease Cause Is Pinpointed With Genome

Article by Nicholas Wade – New York Times
Published: March 10, 2010

Two research teams have independently decoded the entire genome of patients to find the exact genetic cause of their diseases. The approach may offer a new start in the so far disappointing effort to identify the genetic roots of major killers like heart disease, diabetes and Alzheimer’s.

In the decade since the first full genetic code of a human was sequenced for some $500 million, less than a dozen genomes had been decoded, all of healthy people.

Geneticists said the new research showed it was now possible to sequence the entire genome of a patient at reasonable cost and with sufficient accuracy to be of practical use to medical researchers. One subject’s genome cost just $50,000 to decode.

“We are finally about to turn the corner, and I suspect that in the next few years human genetics will finally begin to systematically deliver clinically meaningful findings,” said David B. Goldstein, a Duke University geneticist who has criticized the current approach to identifying genetic causes of common diseases.

Besides identifying disease genes, one team, in Seattle, was able to make the first direct estimate of the number of mutations, or changes in DNA, that are passed on from parent to child. They calculate that of the three billion units in the human genome, 60 per generation are changed by random mutation — considerably less than previously thought.

The three diseases analyzed in the two reports, published online Wednesday, are caused by single, rare mutations in a gene.

In one case, Richard A. Gibbs of the Baylor College of Medicine sequenced the whole genome of his colleague Dr. James R. Lupski, a prominent medical geneticist who has a nerve disease, Charcot-Marie-Tooth neuropathy.

In the second, Leroy Hood and David J. Galas of the Institute for Systems Biology in Seattle have decoded the genomes of two children with two rare genetic diseases, and their parents.

More common diseases, like cancer, are thought to be caused by mutations in several genes, and finding the causes was the principal goal of the $3 billion human genome project. To that end, medical geneticists have invested heavily over the last eight years in an alluring shortcut.

But the shortcut was based on a premise that is turning out to be incorrect. Scientists thought the mutations that caused common diseases would themselves be common. So they first identified the common mutations in the human population in a $100 million project called the HapMap. Then they compared patients’ genomes with those of healthy genomes. The comparisons relied on ingenious devices called SNP chips, which scan just a tiny portion of the genome. (SNP, pronounced “snip,” stands for single nucleotide polymorphism.) These projects, called genome-wide association studies, each cost around $10 million or more.

The results of this costly international exercise have been disappointing. About 2,000 sites on the human genome have been statistically linked with various diseases, but in many cases the sites are not inside working genes, suggesting there may be some conceptual flaw in the statistics. And in most diseases the culprit DNA was linked to only a small portion of all the cases of the disease. It seemed that natural selection has weeded out any disease-causing mutation before it becomes common.

The finding implies that common diseases, surprisingly, are caused by rare, not common, mutations. In the last few months, researchers have begun to conclude that a new approach is needed, one based on decoding the entire genome of patients.

The new reports, though involving only single-gene diseases, suggest that the whole-genome approach can be developed into a way of exploring the roots of the common multigene diseases.

“We need a way of assessing rare variants better than the genomewide association studies can do, and whole-genome sequencing is the only way to do that,” Dr. Lupski said.

With 10 genomes of healthy humans sequenced, Dr. Gibbs, a specialist in DNA sequencing, decided it was time to decode the genome of someone with a genetic disease and asked his colleague Dr. Lupski to volunteer.

Mutations in any of 39 genes can cause Charcot-Marie-Tooth, a disease that impairs nerves to the hands and feet and causes muscle weakness.

Fifty thousand dollars later, Dr. Lupski turned out to have mutations in an obscure gene called SH3TC2. The copy of the gene he inherited from his father is mutated in one place, and the copy from his mother in a second.

Both his parents had one good copy of the gene in addition to the mutated one. A single good copy can generate enough, or nearly enough, of the gene’s product for the nerves to work properly. Dr. Lupski’s mother was free of the disease and his father had only mild symptoms.

In the genetic lottery that is human procreation, two of their eight children inherited good copies of SH3TC2 from each parent; two inherited the mother’s mutation but the father’s good copy and are free of the disease; and four siblings including Dr. Lupski inherited mutated copies from both parents. These four all have Charcot-Marie-Tooth disease. The results are reported in The New England Journal of Medicine.

In Seattle, Dr. Hood and Dr. Galas have also applied whole-genome sequencing to disease. They analyzed the genome of a family of four, in which the two children each have two single-gene diseases, called Miller syndrome and ciliary dyskinesia. With four related genomes available, the researchers could identify the causative genes. They also improved the accuracy of the sequencing because DNA changes that did not obey Mendel’s rules of inheritance could be classed as errors in the decoding process.

The Seattle team believes whole-genome sequencing can be applied to the study of the common multigene diseases and plans to sequence more than 100 genomes next year, starting with multigenerational families.

The family whose genomes they report in Science were sequenced by a company with a new DNA sequencing method, Complete Genomics of Mountain View, Calif., at a cost of $25,000 each. Clifford Reid, the chief executive, said that the company was scaling up to sequence 500 genomes a month and that for large projects the price per genome would soon drop below $10,000. “We are on our way to the $5,000 genome,” he said.

Dr. Reid said the HapMap and genomewide association studies were not a mistake but “the best we could do at the time.” But they have not yet revolutionized medicine, “which we are on the verge of doing,” he said.

Dr. Goldstein, of Duke University, said the whole-genome sequencing approach that was now possible should allow rapid progress. “I think we are finally headed where we have long wanted to go,” he said.

DNAWellnessinfo.com Resource:  http://www.nytimes.com/2010/03/11/health/research/11gene.html

Vital cues for cancer prevention through DNA repairing gene

Naveen Kumar, TNN, Mar 6, 2010, 10.23pm IST

VARANASI: Now, the study of DNA repairing gene using single nucleotide polymorphism (SNP) marker would provide vital cue for cancer prevention, especially neck and head that comprises of as many as seven different types of cancer in the facial region. In addition, the study would also enable early prediction of much feared breast cancer in women.

While a team of scientists is studying the genomics in cancer, especially the squamous cell carcinoma in neck, head and breast region under the Hap Map project, the case studies in the last five years have revealed interesting contribution of DNA repairing genes including P53 associated genes, where SNP can be used as a marker for prompt diagnostic purpose.

Senior scientist Central Drug Research Institute Lucknow Dr SK Rath told TOI on Saturday, “The studies have shown that P53 associated genes play a vital role in DNA repair and act as tumour suppressor. It changes the DNA repair scene and plays pivotal role in protection against mutagenic and cytotoxic effects of DNA damage that also prevents cancer.” Similarly, SNP could also provide vital cue for DNA repairing in BRAC 1 and 2 genes that are believed to cause breast cancer in women, he added.

It is to be mentioned here that Dr Rath is a key member of the team that studied genotype of cancerous and non-cancerous cells under the project in the Xth five-year plan. Now, the team is researching on SNP of different people including smokers and non-smokers, drinkers and non-drinkers, where the cause of cancer

could not be ascertained.

Saying that million of SNPs exist in human genome that occur in gene within the regulatory region, Dr Rath emphasised that the method detects the most common type of variation in the genome, as it cater to small alteration, providing better scope for prediction. The SNP markers are preferred for population genomic disease association and are good indicators of squamous cell carcinoma in neck and head region that includes cancers of oral cavity, pharynx, nasopharynx, oropharynx, hypopharynx and tongue, he added.

Stressing that cancers of neck and head region are growing at alarming rate in states like UP, he said the case studies in Lucknow revealed that out of 100 cancer patients, the number of patients with cancer in the neck and head region increased from 30 to 49 (150 per cent increase) in the last five years. Worldwide, it is the fifth most common type of cancer affecting over one million population annually, he concluded.

DNAWellnessinfo.com Resource:  http://timesofindia.indiatimes.com/city/varanasi/-Vital-cues-for-cancer-prevention-through-DNA-repairing-gene/articleshow/5648729.cms

A First: Diagnosis By DNA

Matthew Herper, 02.25.10, 11:20 AM EST
Forbes Magazine dated March 15, 2010

Last year a five-month-old boy in Turkey stopped gaining weight and became dehydrated despite getting plenty of liquids. Specialists in Istanbul suspected Bartter’s syndrome, a potentially fatal kidney disorder that afflicts one in 100,000 babies, causing dangerously low levels of potassium and salt.

To confirm their hunch they sent a blood sample to Yale Medical School geneticist Richard Lifton. They asked him to determine whether the baby had the gene defect implicated in Bartter’s. But Lifton thought that Bartter’s might not be the culprit. So he did something that would have been prohibitively expensive a few years ago. He deciphered the DNA letters for all the baby’s genes. The gene scan revealed that the baby’s problem was not Bartter’s but something else called congenital chloride diarrhea, which also lowers salt levels. The result means that the baby, now doing better on a special diet, could be treated with drugs if his condition gets worse.

The case, published in the Proceedings of the National Academies of the Sciences in October, may be the first in which the results of DNA sequencing have altered treatment of a patient. Does this herald the beginning of a new kind of medicine in which patients with unexplained symptoms get their DNA sequenced? Yes, says Lifton: “This will be a court of last resort to try and identify causes of disease.”

Gene researchers have talked for years about how sequencing will transform medicine. Now that sequencing is cheap this transformation is under way. The cost of deciphering all 6 billion letters in the human genome has dropped from $1 million in 2007 to less than $20,000 today. Lifton used a two-step method to extract and sequence only the 1% of those letters that contain known genes, lowering the price to $2,500. New DNA sequencers just introduced by Illumina ( ILMN – news – people ) (whose model Lifton used) and Life Technologies ( LIFE – news – people ) could lower the cost of sequencing a whole genome to below $3,000 by year-end.

DNA sequencers haven’t been approved for use in medical testing, and insurers don’t pay for sequencing. But peering into DNA is becoming an option for wealthy patients with rare and scary diseases. Knome, a privately held company in Cambridge, Mass., started out in 2008 charging $350,000 to arrange sequencing and interpret the data for wealthy patrons as a vanity project. Now it offers the scans for as little as $25,000. Chief Executive Jorge Conde says several patients hoping to improve their care are among his customers.

The $600 million annual market for DNA sequencers is still all about research, with Illumina holding a 60% market share. But numerous companies are already jockeying for position in anticipation of a big future medical-test market.

Cancer patients may be among the first to benefit from DNA sequencing technology. In one early example of how this may work, Marco Marra, a researcher at the Michael Smith Genome Sciences Centre in Vancouver, last year sequenced the genes from a tumor that had spread from an 80-year-old patient’s tongue to his lungs. There is no standard therapy for this type of tumor. But the gene scan found the tumor was making large amounts of a growth-promoting protein called RET. When the patient’s medicine was switched to Pfizer ( PFE – news – people )’s Sutent, a drug that blocks this protein, the tumor shrank, according to a report in Nature.

A looming question is how the Food & Drug Administration will regulate sequencing technology. It could treat DNA sequencing like genetic tests and require separate approvals for each use. Some equipment makers hope for a faster path in which doctors practicing a new medical specialty emerge to evaluate and interpret gene scans, as radiologists do with X-rays. Clifford Reid, chief executive of Complete Genomics, which has finished 50 genomes, is skeptical that it will be that easy. “The FDA has been very quiet up until now,” he says. “We all have to expect the FDA to be intimately involved with these new tests.”

DNAWellnessinfo.com Resource:  http://www.forbes.com/forbes/2010/0315/health-illumina-genome-cancer-diagnosis-by-dna.html

Blood Tests May Reveal Tumor Size

Feb. 22, 2010 – cbsnews.com

(CBS) This article was written by Discover’sAndrew Moseman.

Doctors who are torn over how aggressively to treat a cancer patient, not knowing whether a tumor has fully regressed or is coming back, might someday be able to find out just by testing the patient’s blood. In a study forthcoming his week in Science Translational Medicine, John Hopkins researchers say they have tested a way to spot the “fingerprint” of cancer-the changes to the

Jeffery Schloss of the National Human Genome Research Institute, who wasn’t involved in the study, likened the approach to drawing a map. Sequencing the letters of the genetic code would be akin to plotting every house in a large neighborhood. The Hopkins team was looking only for neighborhoods-in particular, neighborhoods out of place compared with where they would be in normal tissue. The researchers in the study looked at tissue from people with breast or bowel cancer, and found multiple DNA rearrangements in each of the samples of cancerous tissue.

In each patient, the genetic changes in the cancerous cells amount to a unique marker of the patient’s tumor, the researchers say. Using blood samples from two of the colorectal cancer patients, they found the test was sensitive enough to detect this marker or “fingerprint” DNA that had been shed by tumors into the bloodstream.

The study’s approach could be invaluable for tracking the progress of a tumor. When a cancer is operated on or treated with radio – or chemotherapy, the levels of the fingerprint should fall, and vanish altogether if the tumor has been eradicated. Indeed, in one of their patients, the study authors saw the cancer biomarker drop after surgery but then rise again, suggesting to them that the cancer wasn’t fully eradicated.

Because the technique requires sequencing a person’s whole genome, it’s not coming to a hospital near you in the immediate future, says study author Bert Vogelstein: “This is really personalized medicine. This is not something off the shelf…. This is something that has to be designed for each individual patient”. But with the cost of genome sequencing rapidly coming down in price, this kind of approach might not be too far away, and doctors could use it to catch a recurring cancer before it’s large enough to be visible to other methods, like CT scans.


By Andrew Moseman
Reprinted with permission from Discover

DNAWellnessinfo.com Resource: http://www.cbsnews.com/stories/2010/02/22/tech/main6232081.shtml