Navigation Links
'Smothered' genes combine with mutations to yield poor outcome in cancer patients
Date:7/15/2008

Johns Hopkins Kimmel Cancer Center researchers have identified a set of genes in breast and colon cancers with a deadly combination of traditional mutations and "smothered" gene activity that may result in poor outcomes for patients.

The Hopkins team showed that this smothering process, called epigenetic inactivation, contributes to the aggressiveness of breast and colon cancer by disrupting biochemical pathways that normally suppress the runaway growth of cells that is the hallmark of cancer. While mutations alter pathways by rewriting the gene's DNA code, epigenetic marks affect genes without changing the code itself.

"Until studies like ours, it was easy to think that if we didn't find gene mutations in certain biochemical pathways linked to breast or colon cancer, then those pathways were normal in such patients," says Stephen Baylin, M.D., the Virginia and D.K. Ludwig Professor for Cancer Research and deputy director of the Kimmel Cancer Center. "Now we know that, in some patients, the pathways involved with newly discovered mutated genes are often more frequently disrupted by epigenetic mechanisms rather than genetic ones."

"That's a powerful insight that could help us diagnose patients quicker, predict the course of their cancer more accurately and in the future treat the disease more effectively," adds Baylin. A report on this work appeared May 27 in PLoS Medicine.

The team made their discovery using microarray technology - special silicon chips carrying pieces of genetic material that allow thousands of genes to be analyzed at one time. For this study, microarrays were tailored to locate cancer-related genes inactivated by an epigenetic process called DNA methylation. This methylation involves the binding of molecules called methyl groups to elements of DNA called cytosines that are located in a gene's "on-off switch." Excess methylation smothers the gene with too many methyl groups and interferes with the gene's normal protein production, setting the stage for a lethal cancer.

Some 189 mutated genes in breast and colon cancers, previously identified by a Kimmel Cancer Center research team, were screened for methylation by Baylin's group. They found 36 genes that were infrequently mutated in cancer, but were "hyper"methylated, often in both breast and colon cancers. After reviewing samples from 30 breast and 20 colorectal cancer patients as well as information from public microarray databases, the researchers found 18 of these genes that were strongly linked to poor outcome of patients with tumors carrying these changes.

For most of the genes, the researchers were able to reverse their epigenetic change and reactivate them in test tubes by stripping off excess methyl groups. This suggests that new treatments designed to reverse hypermethylation could be a simpler and more practical approach to treating cancer than strategies that attempt to replace, deactivate or compensate for mutated genes, according to Baylin.

Baylin also believes that the methlylated genes identified in this study could be inactivated in a broader range of cancers as well. That means the current findings could be extended to other cancers, improving the ability of physicians to predict the course of additional types of tumors, he says.

"We've learned from this study that we must include both genetic and epigenetic changes when we do future microarray analyses to increase our understanding of the genetic basis of cancer," Baylin says. "Such information will provide new details about why cancers start and help us identify which cancers will be particularly aggressive in our patients."


'/>"/>

Contact: Vanessa Wasta
wastava@jhmi.edu
410-955-1287
Johns Hopkins Medical Institutions
Source:Eurekalert

Related biology news :

1. Scientists discover key patterns in the packaging of genes
2. The first autism disease genes
3. Researchers reveal types of genes necessary for brain development
4. UT Southwestern researchers identify new targets for RNAs that regulate genes
5. Texas A&M researchers develop tool to study complex clusters of genes
6. New oral angiogenesis inhibitor offers potential nontoxic therapy for a wide range of cancers
7. Scientists discover DNA knot keeps viral genes tightly corked inside shell
8. Brucella abortus S19 genome sequenced; points toward virulence genes
9. At Boston symposium, NARSAD researchers report on genes and family traits
10. New technique allows targeted inactivation of genes in research model
11. New cheaper method for mapping disease genes
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/10/2016)... India , February 10, 2016 /PRNewswire/ ... --> According to 2016 iris recognition ... identification iris recognition is more widely accepted ... available with both fingerprint and iris recognition ... the user to avoid purchasing two individual ...
(Date:2/4/2016)... , Feb. 4, 2016 The ... apparently one of the most popular hubs of ... MetaHIT and other huge studies of human microbiota, ... past few years, the microbiome space has literally ... biomedical research. This report focuses on biomedical ...
(Date:2/2/2016)... YORK , Feb. 2, 2016 /PRNewswire/ ... facilities are primarily focused on medical screening ... measure point-of-care parameters. Wearable devices that facilitate ... user,s freedom of movement are being bolstered ... for human biomedical signal acquisition coupled with ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... 11, 2016 Non-profit Consortium Aims to ... to Support Research and Discovery --> ... an ambitious plan to sequence 100,000 individuals. It is intended ... at least 7 of North and East Asian countries. ... phase, the project will focus on creating phased reference genomes ...
(Date:2/11/2016)... NEW YORK , Feb. 11, 2016  Bioethics International, ... how medicines are researched, developed, marketed and made accessible to ... BMJ Open had named the publication of the ... for 2015. The publication is also featured as one of ... published in the last year that are most frequently read. ...
(Date:2/11/2016)... Feb. 11, 2016  Dovetail Genomics™ LLC today announced ... program for a planned metagenomic genome assembly service. ... metagenomic genome assembly method in a talk on Friday, ... & Technology conference in Orlando, Fla. ... complex datasets is difficult. Using its proprietary ...
(Date:2/11/2016)... ... February 11, 2016 , ... Global Stem Cells Group, ... Bankok,Thailand-based Global Stem Cells Network (GSCN) to distribute exosome injection and other biological ... Mexico, Costa Rica, Dominican Republic, Colombia, Argentina, Nicaragua, Panama, El Salvador, Venezuela, Peru, ...
Breaking Biology Technology: