Featured Research

from universities, journals, and other organizations

Deep, Integrated Genomic Analysis Re-Classifies Lower-Grade Brain Tumors

Date:
April 8, 2014
Source:
University of Texas M. D. Anderson Cancer Center
Summary:
Comprehensive genomic analysis of low-grade brain tumors sorts them into three categories, one of which has the molecular hallmarks and shortened survival of glioblastoma multiforme. "The immediate clinical implication is that a group of patients with tumors previously categorized as lower grade should actually be treated as glioblastoma patients and receive that standard of care -- temozolomide chemotherapy and irradiation," said the lead author.

Comprehensive genomic analysis of low-grade brain tumors sorts them into three categories, one of which has the molecular hallmarks and shortened survival of glioblastoma multiforme, the most lethal of brain tumors, researchers reported at the American Association for Cancer Research Annual Meeting 2014.

Related Articles


"The immediate clinical implication is that a group of patients with tumors previously categorized as lower grade should actually be treated as glioblastoma patients and receive that standard of care -- temozolomide chemotherapy and irradiation," said lead author Roel Verhaak, Ph.D. assistant professor of Bioinformatics and Computational Biology at The University of Texas MD Anderson Cancer Center.

"Classifying lower grade tumors in these three molecular clusters more accurately characterizes them than current methods used to group and grade tumors," Verhaak said.

The pivotal molecular markers that define the three tumor clusters -- mutational status of the IDH1 and IDH2 genes and loss of chromosome arms 1p and 19q -- are already routinely checked in clinical care, Verhaak noted, so implementing the new categories can be done relatively quickly.

Verhaak and colleagues analyzed data from The Cancer Genome Atlas (TCGA) brain tumor studies.

Lack of IDH1/2 mutations drastically reduces survival

Brain tumors arise in the glia, or supportive cells, of the brain and now are classified by their histology -- characteristics visible via microscopy -- and their cell of origin, either astrocytes or oligodendrocytes.

Classified this way, grade 2 and 3 oligodendrogliomas and astrocytomas demonstrate median overall patient survival ranging from three to ten years. This compares with 14 months for patients with glioblastoma multiforme -- a complex and aggressive astrocytoma. Glioblastomas make up 55-60 percent of gliomas, with lower-grade astrocytomas comprising 15-20 percent of cases, oligodendrocytes 12-20 percent and combination oligo-astrocytomas at 5-10 percent.

The researchers comprehensively analyzed 254 TCGA lower-grade gliomas for gene, protein and micro RNA expression, DNA methylation and gene copy profiles to cluster cases by category. Then they conducted a "cluster of clusters" analysis that encompassed all data.

"The results overwhelmingly point to a natural grouping of lower-grade gliomas into three super clusters based on the mutational status of the IDH1 and IDH2 genes and co-deletion of chromosome arms 1p and 19q," Verhaak said.

Previous TCGA research had shown that glioblastoma patients with mutations of IDH1/IDH2 in their tumors have an improved prognosis. Verhaak said whether these mutations are markers of good prognosis or actually have a role in thwarting tumor progression is not known. Co-deletion of 1p19q has been associated with increased tumor sensitivity to chemotherapy and longer survival for oligodendroglioma patients.

Each molecular group includes tumors from all grades and categories of astrocytoma, oligodendrocytoma and oligo-astrocytoma

The three molecular super clusters of lower grade gliomas have either: •Wild-type IDHI1 and IDH2 with no mutations. These tumors are similar to glioblastoma, with patients' median survival at 18 months. •IDH1/IDH2 mutations and chromosome arms 1p/19q intact. No dominant histology or grade type, median survival of about seven years. •IDH1/IDH2 mutations and co-deletion of 1p/19q. This cluster was composed mainly of oligodendrogliomas (84 percent) and had median survival of about eight years.


Story Source:

The above story is based on materials provided by University of Texas M. D. Anderson Cancer Center. Note: Materials may be edited for content and length.


Cite This Page:

University of Texas M. D. Anderson Cancer Center. "Deep, Integrated Genomic Analysis Re-Classifies Lower-Grade Brain Tumors." ScienceDaily. ScienceDaily, 8 April 2014. <www.sciencedaily.com/releases/2014/04/140408161949.htm>.
University of Texas M. D. Anderson Cancer Center. (2014, April 8). Deep, Integrated Genomic Analysis Re-Classifies Lower-Grade Brain Tumors. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2014/04/140408161949.htm
University of Texas M. D. Anderson Cancer Center. "Deep, Integrated Genomic Analysis Re-Classifies Lower-Grade Brain Tumors." ScienceDaily. www.sciencedaily.com/releases/2014/04/140408161949.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. 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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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