Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene profiling predicts resistance to breast cancer drug Herceptin

22.02.2007
Using gene chips to profile tumors before treatment, researchers at Harvard and Yale Universities found markers that identified breast cancer subtypes resistant to Herceptin, the primary treatment for HER2-positive breast cancer. They say this advance could help further refine therapy for the 25 to 30 percent of breast cancer patients with this class of tumor.

In the February 15 issue of Clinical Cancer Research, the researchers found that HER2-positive tumors that did not respond to Herceptin expressed certain basal markers, growth factors and growth factor receptors. One of these, insulin-growth factor receptor 1(IGF-1R), was associated with a Herceptin response rate that was half that of tumors that did not express IGF-1R.

They also discovered that resistant tumors continue to over-express the HER2 growth factor protein -- an important finding given that many scientists had thought that loss of HER2 was likely responsible for Herceptin resistance.

"Herceptin has revolutionized the care of HER2-positive breast cancer for many patients, but unfortunately, not for some. This work demonstrates that digging deeper into the molecular subtypes of these tumors helps us understand why some tumors are resistant and may point to ways to remedy that," said the study’s lead author, Lyndsay Harris, M.D., associate professor and Director of the Breast Cancer Disease Unit at Yale University Medical Center.

... more about:
»HER2 »HER2-positive »Herceptin »breast cancer

If additional studies validate these findings, it may be possible to select those patients that will be resistant to Herceptin and treat them with additional drugs to restore Herceptin sensitivity, according to Harris. "Our goal is to see what the tumor tells us before any treatment starts and tailor therapy accordingly," she said.

To determine Herceptin sensitivity, investigators took a small tumor biopsy from 48 patients with newly diagnosed and operable stage II/III breast cancer. They examined the biopsy tissue using both single and multi-gene microarrays, looking for RNA that has been activated to produce proteins.

They then treated the women with a combination of Herceptin and the chemotherapy drug Navelbine weekly for 12 weeks. Although this is not the first study to test Herceptin use before surgery, it is the first to examine the use of Navelbine, a drug approved for lung cancer treatment, in combination with Herceptin to treat HER2-positive tumors. "We were motivated to use Navelbine because we found it has few side effects when used to treat metastatic breast cancer," said Harris, who conducted much of the research study at Harvard before moving to Yale.

After treatment, the tumors were surgically removed and gene chips were again used to examine RNA transcription -- making these investigators the first to use such a technique on Herceptin treated tumors. "This kind of profiling has been done to look at response to chemotherapy drugs, but not at Herceptin resistance," Harris said.

The researchers then divided tumors into groups depending on how well they responded to therapy, and examined the baseline and post-therapy RNA profiles to find genes that were more commonly expressed in Herceptin sensitive and Herceptin resistant tumors.

They first found that some single gene markers, such as HER2 and ER (estrogen receptor), did not change in the majority of tumors. "That tells us that the cancer cells are still creating HER2 surface proteins even as Herceptin is being used, and that means HER2 loss does not appear to be a mechanism of resistance in early stage breast cancer," Harris said.

Then, using multigene chips, the researchers derived a bevy of transcribed genes that likely play a role in Herceptin resistance. Some, such as IGF-1R, were suspected, because this protein is frequently over-expressed in breast tumors, Harris says, but others were not. For example, non-responding tumors were more likely to express genes associated with basal-like breast cancer, which the researchers found to be surprising. "Most basal-like tumors are HER2-negative," Harris said.

Herceptin resistant tumors were also more likely to express a variety of growth factors, suggesting that "activation of parallel pathways may release tumors from dependence on HER2 proliferation and survival," she said.

Although the study was not designed to look at outcome, the researchers determined that 42 of 48 patients had a clinical response (16 complete responses and 26 partial responses) from the neoadjuvant treatment, and five patients experienced cardiotoxicity. After a median 2.6-year-follow-up, three of 48 patients relapsed and one died of her disease.

Greg Lester | EurekAlert!
Further information:
http://www.aacr.org

Further reports about: HER2 HER2-positive Herceptin breast cancer

More articles from Life Sciences:

nachricht Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>