Archive for the ‘Methylation’ Category

New medical device headed to KU could be ‘revolutionary’ tool for breast cancer

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Posted 19 Mar 2012 — by James Street
Category Breast Cancer, Gamma Ray, Gamma Ray, Physics and Engineering

KU Cancer Center to conduct trials on GammaPod, a device said to eliminate small breast tumors without surgery.

By ALAN BAVLEY

The Kansas City Star

It hasn’t been tried on a single patient yet, and already doctors are calling this new radiation therapy device for breast cancer “paradigm-changing” and “revolutionary.”

It’s the GammaPod, coming later this year to the University of Kansas Cancer Center.

Enthusiastic doctors say this $3 million-plus piece of technology could make it possible for the first time to eradicate early-stage breast tumors without surgery; they’ll be nuked to oblivion by just a week of intensely focused radiation treatments. No risk of scars, infections or breast deformities.

That’s sure to pique the interest of the roughly 150,000 women who undergo lumpectomies each year in the United States.

But don’t get your hopes up just yet, more skeptical doctors counsel. Nobody before has been able to destroy breast tumors with radiation alone. And it will take years of clinical trials before there’s proof that GammaPod works as well as the conventional combination of an operation to remove a lump in the breast followed by about six weeks of radiation therapy.

So far, the GammaPod has stayed under the media’s radar, deliberately, its manufacturer says, to avoid raising public expectations prematurely.

That’s likely to change later this year when the devices are delivered first to the University of Maryland, where it was invented, then to KU and the University of Texas Southwestern Medical Center in Dallas, and shortly after that, to Allegheny General Hospital/Western Pennsylvania Hospital in Pittsburgh and Thomas Jefferson University Hospital in Philadelphia.

These five medical centers will conduct the first clinical trials of the GammaPod to develop the evidence that will be needed before it can be considered a worthwhile alternative to surgery.

But like other high-tech marvels that promise to make medical treatment safer, less painful and more convenient, GammaPods could proliferate at hospitals around the country long before all the data are in.

As early as next year, the GammaPod’s manufacturer, Xcision Medical Systems of Columbia, Md., expects to ask the U.S. Food and Drug Administration to green-light commercial sales of the device. FDA rules allow devices to be sold without clinical trials to back them up.

“Our goal is to make this commercially available in community settings around the world,” said Xcision vice president Will Wells. “A 10 percent (U.S.) market penetration after a few years would be about right.”

That translates into sales of about 200 GammaPod systems in just the first three years that it’s on the market, Wells estimated.

That comes as no surprise to Donald Patrick, a health policy researcher at the University of Washington and co-author of the book “Hope or Hype: The Obsession with Medical Advances and the High Cost of False Promises.”

“All sorts of things are touted as effective. The public demands them,” Patrick said. “We want something that’s easy and helps us live forever. That’s the American way — anything new.”

• • •

Medical devices that have entered the market before there was substantial evidence they improved care range from $1 million surgical robots to $100 million proton cancer therapy centers.

The GammaPod uses a proven technology called stereotactic body radiation therapy to successfully obliterate inoperable brain tumors and hard-to-reach lung and liver cancers. While the technology has never been used on breast tumors, that may not stop Xcision from getting swift FDA approval to go to market.

The FDA usually considers new stereotactic radiation devices as similar to existing ones, said Jim Keller, vice president of the nonprofit ECRI Institute, which does research on the effectiveness of medical devices. As long as a manufacturer can show that its new device is as safe and effective as others already on the market, FDA will give its assent without additional tests on patients.

Stereotactic radiation devices generally are approved for treatment of “lesions, tumors or conditions anywhere in the body,” Keller said.

But ultimately, the FDA’s ruling, Keller said, will “come down to their marketing claims, how the manufacturer plans to market the clinical effects.”

Wells of Xcision is mindful of what he says.

“We don’t want to create a buzz around something we can’t deliver,” he said. “This is early on. It’s best for us to gain data … as to not hype or overdraw our own technology prematurely.”

That hasn’t stopped others from being bolder.

“We can deliver a high enough dose to (neutralize) the tumor,” the GammaPod’s inventor, Cedric Yu, said in a University of Maryland press release from 2010.

“The traditional three-month ordeal can be shortened to three treatments only,” Yu said. “You don’t need surgery. You don’t need standard radiation. No needle, knife, pain, anesthesia, and no scar.”

By last November, in a keynote address to a University of Maryland breast cancer conference, Yu was calling his device “a paradigm-changing technology.”

“I don’t use this word lightly, but I would consider this device revolutionary,” said radiation oncologist Parvesh Kumar, the associate director of clinical research at KU Cancer Center. “This is absolutely huge.”

Kumar will lead research on the GammaPod at KU.

If it’s successful at eradicating tumors, the GammaPod would free women not only from the complications of breast surgery, but the costs as well, about $20,000 to $30,000 for a lumpectomy, Kumar estimated.

The cost of GammaPod treatments would likely be similar to that of conventional radiation, about $20,000 to $40,000, he said.

• • •

 

The five medical centers receiving the first GammaPods are developing a detailed five-year experimental plan called a protocol for testing the device, Kumar said.

The initial patients will be post-menopausal women with less-aggressive, early-stage breast cancer. Only women most likely to have a favorable outcome from treatment — those with small tumors and cancer that hasn’t spread to lymph nodes — will be admitted to the clinical trial.

At first, women in the study will undergo a conventional lumpectomy and receive GammaPod treatments either before or after their operation, Kumar said. Treatments given before surgery will show the researchers how effective the radiation is at killing breast tumors and allow them to determine what dose is needed.

Women will lie face down on the GammaPod’s specially designed table. Through a large gap in the table, a cup will lock onto the breast to keep it absolutely stationary and precisely positioned for the radiation.

From beneath the table, beams of radiation will strike the tumor from different directions. None of the individual beams will be strong enough to harm the healthy tissue they pass through before reaching the tumor. But the combined strength of the beams bombarding the tumor will be calculated to give it a lethal dose.

“We think there will be virtually no toxicity” beyond the tumor, Kumar said. And nothing in the protocol will result in a poorer outcome for patients than conventional treatment, he said.

But with standard therapy already shown to be effective, entering the protocol for the GammaPod is “perhaps not for the faint of heart,” advised Phillip Devlin, an associate professor of radiation oncology at Harvard Medical School.

“To date, there is no therapy that replaces surgery in the treatment of early breast cancer,” Devlin said.

In the 1950s, researchers tried using high doses of radiation to get rid of breast tumors without surgery, Devlin said. The radiation damaged healthy breast tissue but didn’t kill the tumors.

“One shouldn’t forget history,” he said.

Stereotactic body radiation therapy has worked to good effect against tumors in other organs, Devlin said. It’s not unreasonable to think it might work against breast tumors.

“But it’s a hypothesis to test.” he said. Meanwhile, “the current paradigm (of surgery and radiation) saves a lot of women.”

How will hospitals use their GammaPods before clinical trials can determine whether it eradicates breast tumors?

“That’s a great question, but I can’t answer it,” said Wells of Xcision. “We make a (radiation) system…the actual prescription is not something we dictate.”

To reach Alan Bavley, call 816-234-4858 or send email to abavley@kcstar.com.

A twist on epigenetic therapy vs cancer

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Posted 01 Dec 2011 — by James Street
Category BAI1, Brain, Epigenetics, genetic research, Methylation

November 30, 2011

Epigenetic therapies against cancer have attracted considerable attention in recent years. But many of the drugs currently being studied as epigenetic anticancer therapies may have indiscriminate effects. A recent paper in Cancer Research from brain cancer researcher Erwin Van Meir’s laboratory highlights a different type of target within cancer cells that may be more selective. Postdoctoral fellow Dan Zhu is the first author of the paper.

Erwin Van Meir, PhD

The basic idea for epigenetic therapy is to focus on how cancer cells’ DNA is wrapped instead of the mutations in the DNA. Cancer cells often have aberrant patterns of methylation or chromatin modifications. Methylation is a punctuation-like modification of DNA that usually shuts genes off, and chromatin is the term describing DNA when it is clothed by proteins such as histones, a form of packaging that determines whether a gene is on or off.

In contrast to mutations that are hard-wired in the DNA, changes in cancer cells’ methylation or chromatin may be reversible with certain drug treatments. But a puzzle remains: if a drug wipes away methylation indiscriminately, that might turn on an oncogene just as much as it might restore a tumor suppressor gene.

The ability of an inhibitor of methylation to treat cancer may depend on cell type and context, explains chromatin/methylation expert and co-author Paula Vertino. She points out that one well-known methylation inhibitor, azacytidine (Vidaza), is a standard treatment for myelodysplastic syndrome, but the strategy of blanket-inhibition of methylation can’t be expected to work for all cancers. A similar challenge exists for agents that target histone acetylation in a global fashion.

Epigenetic therapies seek to modify how DNA is packaged in the cell.

Van Meir’s laboratory has been studying a tumor suppressor protein called BAI1 (brain angiogenesis inhibitor 1), which prevents tumor and blood vessel growth. BAI1 is produced by brain cells naturally, but is often silenced epigenetically in glioblastoma cells. His team found that azacytidine de-represses the BAI1 gene.

Methylation won’t turn a gene off without the help of a set of proteins that bind preferentially to methylated DNA. These proteins are what recognize the methylation state of a given gene and recruit repressive chromatin. Zhu and colleagues in Van Meir’s group found that one particular methyl-binding protein, MBD2, is overproduced in glioblastoma and is enriched on the BAI1 gene.

“Taken together, our results suggest that MBD2 overexpression during gliomagenesis may drive tumor growth by suppressing the anti-angiogenic activity of a key tumor suppressor. These findings have therapeutic implications since inhibiting MBD2 could offer a strategy to reactivate BAI1 and suppress glioma pathobiology,” the authors write.

By itself, MBD2 appears to be dispensable, since mice seem to be able to develop and survive without it. Not having it even seems to push back against tumor formation in the intestine, for example. Targeting MBD2 may represent an alternative way to steer away from cancer cells’ altered state.

Van Meir cautions: “We need to have a better understanding of all the genes that are turned on or off by silencing MBD2 in a given cancer before we can envision to use this approach for therapy.”

Vertino, Shaoman Yin and Steven Hunter, all at Emory, are co-authors on the paper. The work was supported by grants from the NIH and the Southeastern Brain Tumor Foundation and the Emory University Research Council.