Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic mutations that cause common childhood brain tumors identified

23.07.2012
Researchers at the Stanford University School of Medicine and Lucile Packard Children's Hospital have identified several gene mutations responsible for the most common childhood brain tumor, called medulloblastoma, adding evidence to the theory that the diagnosis is a group of genetically distinct cancers with different prognoses. These and accompanying findings are likely to lead to less-toxic, better-targeted treatment approaches over the next two years, the researchers said.

"We tend to treat all medulloblastomas as one disease without taking into account how heterogeneous the tumors are at the molecular level," said Yoon-Jae Cho, MD, an assistant professor of neurology and neurological sciences at Stanford, a pediatric neurologist at Packard Children's and the senior author of the new research. "This paper represents a finer-grained view of the genetic landscape of these tumors and provides us with some leads on how to develop new therapies."

The research, which will appear online in Nature July 22, is part of a large, ongoing effort to characterize genetic errors in medulloblastoma. Two companion studies on which Cho is a co-author will be published simultaneously with his paper. The three papers came from a consortium that involves scientists at Stanford, Packard Children's, the Broad Institute, Children's Hospital Boston, the Dana-Farber Cancer Institute, the German Cancer Research Center, Brandeis University and the Hospital for Sick Children in Toronto.

Current treatment for medulloblastoma, which originates in the cerebellum and affects about 250 U.S. children each year, begins with surgery to remove as much of the tumor as possible. Patients then receive a combination of radiation and chemotherapy, but the treatments are not tailored to the tumor's genetic characteristics.

Cho's team extracted DNA from 92 medulloblastoma tumors and compared it with DNA from matched blood samples from the same patients, uncovering 12 significant "point mutations" — single-letter errors in the genetic code — that occurred frequently in the brain cancer. A handful of the mutations had been previously identified in smaller studies of medulloblastoma, but several mutations were novel in both medulloblastoma and in cancer.

Among the newly identified mutations was one in an RNA helicase gene, DDX3X, which Cho said is the second-most common mutation in medulloblastoma tumors. "Mutations in this gene have now also been identified in other tumor types, such as chronic lymphocytic leukemia, and head and neck tumors," he said.

However, the researchers found that it was rare for the same gene mutated in several different patients' tumors. More commonly, mutations involving a set of genes regulating a single biological pathway were found in the tumors — a pattern that is emerging across cancer genome sequencing efforts.

Though no single tumor in the study carried all 12 mutations, the researchers were able to categorize the tumors according to which mutations they possessed. "We now understand that there are certain tumors with particular genetic signatures that are really resistant to standard treatments," Cho said. Children with medulloblastoma do not routinely have their tumors' genetic signatures characterized, but Cho believes that such characterization coupled with targeted therapies could greatly enhance tumor treatment.

About two-thirds of medulloblastoma patients now survive five years past diagnosis, but many survivors suffer lasting physical or intellectual side effects from their cancer treatments. Drugs tailored to a tumor's genetic profile have the potential to save more patients while reducing side effects, Cho said.

Several of the mutations discovered affect cellular signals that switch large groups of genes on and off. "The dysregulation of these 'epigenetic programs' is becoming a common theme not only in medulloblastoma but across cancer," Cho said. Such pathways may be good targets for cancer drugs; indeed, drugs targeting one such pathway (histone methyltransferases) are currently in pre-clinical development, while agents against another pathway (Hedgehog signaling pathway) are entering phase-2 clinical trials for medulloblastoma.

Cho is the co-chair of a committee within the Pediatric Brain Tumor Consortium that guides which drugs should be moved into clinical trials next. "Our plan is that within the next one to two years we will be able to offer kids a new set of compounds that have a clear biological rationale based on our genomic studies." Cho said. "We want to make sure we're being careful of what we move forward with, but at the same time, for some of these kids we don't have many, if any, effective and durable treatment options."

Cho's collaborators at Stanford included research associate Furong Yu; Gerald Crabtree, PhD, professor of pathology and of developmental biology and a member of the Stanford Cancer Institute; and life science research assistant Amanda Kautzman.

The research was funded by the National Institutes of Health, a St. Baldrick's Foundation Career Development Award, the Beirne Faculty Scholar endowment at Stanford University, German Cancer Aid, the BMBF ICGC-PedBrain project, the Howard Hughes Medical Institute, the Pediatric Brain Tumor Foundation, the Canadian Institutes of Health Research, the Hospital for Sick Children and the Mullarkey Research Fund. Cho consults for Novartis to help develop biomarkers for the company's clinical trial design.

Information about Stanford's Department of Neurology and Neurological Sciences, which also supported this research, is available at http://neurology.stanford.edu/.

The Stanford University School of Medicine consistently ranks among the nation's top medical schools, integrating research, medical education, patient care and community service. For more news about the school, please visit http://mednews.stanford.edu. The medical school is part of Stanford Medicine, which includes Stanford Hospital & Clinics and Lucile Packard Children's Hospital. For information about all three, please visit http://stanfordmedicine.org/about/news.html.

Lucile Packard Children's Hospital at Stanford is an internationally recognized 311-bed hospital, research center and leading regional medical network providing the full complement of services for the health of children and expectant mothers. In partnership with the Stanford University School of Medicine, our world-class doctors and nurses deliver innovative, family-centered care in every pediatric and obstetric specialty, tailored to every patient. Packard Children's is annually ranked as one of the nation's best pediatric hospitals by U.S. News & World Report and is the only Northern California children's hospital with specialty programs ranked in the U.S. News Top 10. Learn more about us at www.lpch.org and about our continuing growth at growing.lpch.org. Friend us on Facebook, watch us on YouTube and follow us on Twitter.

PRINT MEDIA CONTACT: Erin Digitale at (650) 724-9175 (digitale@stanford.edu)
BROADCAST MEDIA CONTACT: Robert Dicks at (650) 497-8364 (rdicks@lpch.org)

Erin Digitale | EurekAlert!
Further information:
http://www.stanford.edu

More articles from Life Sciences:

nachricht Polarization of Br2 molecule in vanadium oxide cluster cavity and new alkane bromination
13.07.2020 | Kanazawa University

nachricht Researchers present concept for a new technique to study superheavy elements
13.07.2020 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron cryo-microscopy: Using inexpensive technology to produce high-resolution images

Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal "PLOS ONE".

Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new...

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Black phosphorus-based van der Waals heterostructures for mid-infrared light-emission applications

13.07.2020 | Physics and Astronomy

Polarization of Br2 molecule in vanadium oxide cluster cavity and new alkane bromination

13.07.2020 | Life Sciences

Researchers present concept for a new technique to study superheavy elements

13.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>