Featured Research

from universities, journals, and other organizations

'Smothered' Genes Combine With Mutations To Yield Poor Outcome In Cancer Patients

Date:
July 15, 2008
Source:
Johns Hopkins Medical Institutions
Summary:
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.

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.

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."

Participants in the study included Timothy Chan, Sabine Glockner, Joo Mi Yi, Wei Chen, Leslie Cope, James Herman, Victor Velculescu, Kornel Schuebel, and Nita Ahuja of Johns Hopkins, and Leander Van Neste of Ghent University, Belgium.

A report on this work appeared May 27 in PLoS Medicine. This work was supported by the National Institute of Environmental Health Sciences and the National Cancer Institute.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "'Smothered' Genes Combine With Mutations To Yield Poor Outcome In Cancer Patients." ScienceDaily. ScienceDaily, 15 July 2008. <www.sciencedaily.com/releases/2008/07/080715125928.htm>.
Johns Hopkins Medical Institutions. (2008, July 15). 'Smothered' Genes Combine With Mutations To Yield Poor Outcome In Cancer Patients. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2008/07/080715125928.htm
Johns Hopkins Medical Institutions. "'Smothered' Genes Combine With Mutations To Yield Poor Outcome In Cancer Patients." ScienceDaily. www.sciencedaily.com/releases/2008/07/080715125928.htm (accessed April 24, 2014).

Share This



More Health & Medicine News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Companies Ramp Up Wellness to Lower Health Costs

Companies Ramp Up Wellness to Lower Health Costs

AP (Apr. 24, 2014) That little voice telling you to exercise, get in shape and get healthy is probably coming from your boss. More companies are beefing up wellness programs to try and cut down their health care costs. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
FDA Wants To Ban Sales Of E-Cigarettes To Minors

FDA Wants To Ban Sales Of E-Cigarettes To Minors

Newsy (Apr. 24, 2014) The Food and Drug Administration wants to crack down on the use of e-cigarettes, banning the sale of the product to minors. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins