Cancer debate: Are tumors fueled by stem cells?

August 1, 2012 by MALCOLM RITTER

How can a cancer come back after it's apparently been eradicated? Three new studies from American, Belgian, British and Dutch researchers are bolstering a long-debated idea: that tumors contain their own pool of stem cells that can multiply and keep fueling the cancer, seeding regrowth.

If that's true, scientists will need to find a way to kill those cells, apart from how they attack the rest of the .

in healthy tissues are known for their ability to produce any kind of cell. The new research deals with a different kind, cancer stem cells. Some researchers, but not all, believe they lurk as a persisting feature in tumors.

Over the past decade, studies have found evidence for them in tumors like breast and colon cancers. But this research has largely depended on transplanting human cancer cells into mice that don't have immune systems, an artificial environment that raises questions about the relevance of the results.

Now, three studies reported online Wednesday in the journals Nature and Science present evidence for cancer stem cells within the original tumors. Again, the research relies on mice. That and other factors mean the new findings still won't convince everyone that cancer stem cells are key to finding more powerful treatments.

But researcher Luis Parada, of the University of Texas Southwestern Medical Center in Dallas, believes his team is onto something. He says that for the type of brain tumor his team studied, "we've identified the true enemy."

If his finding applies to other cancers, he said, then even if chemotherapy drastically shrinks a tumor but doesn't affect its supply of cancer stem cells, "very little progress has actually been made."

The three studies used labeling techniques to trace the ancestry of cells within mouse tumors.

Collectively, they give "very strong support" to the cancer stem cell theory, said Jeffrey M. Rosen, a professor of at Baylor College of Medicine in Houston. He did not participate in the work but supports the theory, which he said is widely accepted.

Parada's team worked with mice genetically primed to develop a certain type of brain tumor. The scientists genetically labeled particular cells in the tumor and then attacked the cancer with the same drug given to human patients. It kills growing tumor cells and temporarily stops the cancer's growth.

After treatment, when the tumor started growing again in the mice, the researchers showed that the vast majority, if not all, of its new cells had descended from the labeled cells. Apparently these were the tumor's cancer stem cells, they concluded.

Parada said his team is now trying to isolate cancer stem cells from mouse brain cancers to study them and perhaps get some leads for developing therapies to eradicate them.

He also said that preliminary study of human is producing results consistent with what his team found in the mice.

Parada's study appears in Nature. In a second Nature report, British and Belgian researchers found evidence for cancer stem cells in early stage skin tumors in mice. And in the journal Science, a Dutch group found such evidence in mouse intestinal polyps, which are precursors to colon cancer.

Scott Kern of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in Baltimore is skeptical about whether tumors contain cancer stem cells. He said that since the new studies didn't involve human tumors, it's not clear how relevant they are to people.

The two European studies focused largely on lesions that can lead to tumors, he said. And as for Parada's brain cancer study, he said he believed the results could be explained without relying on the cancer stem cell theory.

Explore further: Study suggests new treatment target for glioblastoma multiforme

More information: Nature papers are: DOI: 10.1038/nature11287 , DOI: 10.1038/nature11344. Science paper is: DOI: 10.1126/science.1224676

Journal reference: Nature search and more info website Science search and more info website

shares

Related Stories

Study suggests new treatment target for glioblastoma multiforme

August 1, 2012
A study by UT Southwestern Medical Center researchers published online today in Nature reveals new insight into why the most common, deadly kind of brain tumor in adults recurs and identifies a potential target for future ...

Cancer stem cell vaccine in development shows antitumor effect

April 2, 2012
Scientists may have discovered a new paradigm for immunotherapy against cancer by priming antibodies and T cells with cancer stem cells, according to a study published in Cancer Research, a journal of the American Association ...

New role for Vascular Endothelial Growth Factor in regulating skin cancer stem cells

October 19, 2011
Skin squamous cell carcinomas are amongst the most frequent cancers in humans. Recent studies suggest that skin squamous cell carcinoma, like many other human cancers, contain particular cancer cells, known as cancer stem ...

Stem cells, potential source of cancer-fighting T cells

September 20, 2011
Adult stem cells from mice converted to antigen-specific T cells -- the immune cells that fight cancer tumor cells -- show promise in cancer immunotherapy and may lead to a simpler, more efficient way to use the body's immune ...

Recommended for you

Brain powered: Increased physical activity among breast cancer survivors boosts cognition

September 19, 2017
It is estimated that up to 75 percent of breast cancer survivors experience problems with cognitive difficulties following treatments, perhaps lasting years. Currently, few science-based options are available to help. In ...

Targeted antibiotic use may help cure chronic myeloid leukaemia

September 19, 2017
The antibiotic tigecycline, when used in combination with current treatment, may hold the key to eradicating chronic myeloid leukaemia (CML) cells, according to new research.

Researchers compose guidelines for handling CAR T cell side effects

September 19, 2017
Immune-cell based therapies opening a new frontier for cancer treatment carry unique, potentially lethal side effects that provide a new challenge for oncologists, one addressed by a team led by clinicians at The University ...

Bone marrow protein a 'magnet' for passing prostate cancer cells

September 19, 2017
Scientists at the University of York have shown that a protein in the bone marrow acts like a 'magnetic docking station' for prostate cancer cells, helping them grow and spread outside of the prostate.

Brain cancer breakthrough could provide better treatment

September 19, 2017
A new discovery about the most common type of childhood brain cancer could transform treatment for young patients by enabling doctors to give the most effective therapies.

A new paradigm for treating transcription factor-driven cancers

September 18, 2017
In the current issue of Proceedings of the National Academy of Sciences, researchers from Nationwide Children's Hospital describe a new paradigm for treating transcription factor-driven cancers. The study focuses on Ewing ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.