News / Health

Study Identifies Stem Cells as Cancer Source

Human embryonic stem cellsHuman embryonic stem cells
Human embryonic stem cells
Human embryonic stem cells
Jessica Berman
Scientists have found evidence that cancerous tumors might originate as stem cells - undifferentiated master cells which can grow into any tissue in the body.  Investigators say if this proves true, it could provide a new way to prevent or cure cancer. 

Stem cells are primitive structures in the human body that normally transform themselves into healthy, specialized tissue, everything from blood and bone cells to heart and liver cells.  Now there is evidence that stem cells can also develop into cancer cells that multiply into life-threatening tumors.

The conventional theory of cancer formation is that it begins with the division of a single mutated cell.  The new study challenges this theory with evidence that mutated, cancerous cells may develop directly from stem cells.   

Luis Parada, head of developmental biology at the University of Texas Southwestern Medical Center in Dallas, and his colleagues studied an aggressive, lethal form of human brain cancer called glioblastoma multiforme in genetically bred mice.  The cancer is usually fatal within a year of diagnosis.  Researchers used chemotherapy on the rodents that temporarily halted the growth of their tumors.  But when investigators stopped the drug, the cancer came back.  Parada says a molecular analysis showed the tumors recurred because a small number of stem cells clustered within the brain tissue began dividing, producing new tumor cells.  

But when a group of mice with glioblastoma were given both chemotherapy and a drug that destroyed the stem cells in their brain tissue, their cancer was cured.

Parada says the findings could radically change the way cancer is treated.

“Then it’s no longer valid to evaluate the volume of a tumor and say whether therapy is working or not.  What will be important is to know is how that therapy is affecting the cancer stem cells within the tumor,” Parada said.

Two other independent studies published this week provide additional evidence that stem cells may be the starting point for cancerous tumors.   One team of researchers from Universite´ Libre de Bruxelles in  Brussels, Belgium, and the Wellcome Trust Cancer Research Institute in Britain looked at the role of the master cells in the development of squamous cell carcinoma, a form of skin cancer.

Another group of investigators at the University Medical Center in Utrecht, the Netherlands, engineered a multi-colored model of an intestinal tumor known as an adenoma so they could trace the progression of stem cells to an early-stage tumor.  Researchers tagged the master cells with a red color and watched as they produced a protein that stimulated the growth of pre-cancerous blue cells.

Researcher Hugo Snippert, who created the adenoma model, says there can be many genetic mutations in cells that don’t cause cancer.  He says it’s only when the stem cells are mutated that cancer develops.

“It’s really essential that you get rid of the cancer stem cells because they are tiny, they are low numbers.  But they are able to grow and to give rise and fuel tumor growth really fast,” Snipert said.

University of Texas researcher Luis Parada believes stem cells develop random mutations with age.  And he says his lab is studying a potential cure for cancer that would focus on destroying these mutating stem cells as soon as they could be detected.

“And we are very optimistic that in so doing, we are on the verge of discovering viable targets that are unique to these cells,” Parada explained.

He says researchers are still mapping the locations of stem cell clusters in all human organ tissues where cancers are known to develop.
A series of articles on the role of mutated stem cells in the development of cancer are published jointly in the journals Nature and Science.

You May Like

Multimedia Brussels Schools, Metro Reopen Under Heavy Guard

City remains under the highest threat alert level due to what authorities have described as a 'serious and imminent' threat of attack

Video Debt-ridden Refugees Await Onslaught of Lebanese Winter

Aid agencies are attempting to reduce potentially devastating consequences of freezing conditions and snowstorms that killed eight last year, including three Syrian refugees

Americans Think About Strange Stuff at Thanksgiving

Millions of Americans are celebrating Thanksgiving, but they’re not necessarily thinking about turkey and stuffing

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
After Paris Attacks, France Steps Up Fight Against ISi
November 24, 2015 3:04 AM
The November 13 Paris attacks have drawn increased attention to Syria, where many of the suspected perpetrators are said to have received training. French President Francois Hollande is working to build a broad international coalition to defeat Islamic State in Syria and in Iraq. Zlatica Hoke reports.

Video After Paris Attacks, France Steps Up Fight Against IS

The November 13 Paris attacks have drawn increased attention to Syria, where many of the suspected perpetrators are said to have received training. French President Francois Hollande is working to build a broad international coalition to defeat Islamic State in Syria and in Iraq. Zlatica Hoke reports.

Video US, Cambodian Navies Pair Up in Gulf of Thailand

The U.S. Navy has deployed one of its newest and most advanced ships to Cambodia to conduct joint training drills in the Gulf of Thailand. Riding hull-to-hull with Cambodian ships, the seamen of the USS Fort Worth are executing joint-training drills that will help build relations in Southeast Asia. David Boyle reports for VOA from Preah Sihanouk province.

Video Americans Sharpen Focus on Terrorism

Washington will be quieter than usual this week due to the Thanksgiving holiday, even as Americans across the nation register heightened concerns over possible terrorist threats. VOA’s Michael Bowman reports new polling data from ABC News and the Washington Post newspaper show an electorate increasingly focused on security issues after the deadly Islamic State attacks in Paris.

Video World Leaders Head to Paris for Climate Deal

Heads of state from nearly 80 countries are heading to Paris (November 30-December 11) to craft a global climate change agreement. The new accord will replace the Kyoto Protocol on Climate Change that expired in 2012.

Video Uncertain Future for Syrian Refugee Resettlement in Illinois

For the trickle of Syrian refugees finding new homes in the Midwest city of Chicago, the call to end resettlement in many U.S. states is adding another dimension to their long journey fleeing war. Organizations working to help them integrate say the backlash since the Paris attacks is both harming and helping their efforts to provide refugees sanctuary. VOA's Kane Farabaugh reports.

Video Creating Physical Virtual Reality With Tiny Drones

As many computer gamers know, virtual reality is a three-dimensional picture, projected inside special googles. It can fool your brain into thinking the computer world is the real world. But If you try to touch it, it’s not there. Now Canadian researchers say it may be possible to create a physical virtual reality using tiny drones. VOA’s George Putic reports.

Video New American Indian Village Takes Visitors Back in Time

There is precious little opportunity to experience what life was like in the United States before its colonization by European settlers. Now, an American Indian village built in a park outside Washington is taking visitors back in time to experience the way of life of America's indigenous people. Carol Pearson narrates this report from VOA's June Soh.

Video Even With Hometown Liberated, Yazidi Refugees Fear Return

While the northern Iraqi town of Sinjar has been liberated from Islamic State forces, it's not clear whether Yazidi residents who fled the militants will now return home. VOA’s Mahmut Bozarslan talked with Yazidis, a religious and ethnic minority, at a Turkish refugee camp in Diyarbakır. Robert Raffaele narrates his report.

Video Nairobi Tailors Make Pope Francis’ Vestments

To ensure the pope is properly attired during his visit, the Kenya Conference of Catholic Bishops asked the Dolly Craft Sewing Project in the Nairobi slum of Kangemi to make the pope's vestments, the garments he will wear during the various ceremonies. Jill Craig reports.

Video Cross-Border Terrorism Puts Europe’s Passport-Free Travel in Doubt

The fallout from the Islamic State terror attacks in Paris has put the future of Europe’s passport-free travel area, known as the "Schengen Zone," in doubt. Several of the perpetrators were known to intelligence agencies, but were not intercepted. Henry Ridgwell reports from London European ministers are to hold an emergency meeting Friday in Brussels to look at ways of improving security.

Video El Niño Brings Unexpected Fish From Mexico to California

Fish in an unexpected spectrum of sizes, shapes and colors are moving north, through El Niño's warm currents from Mexican waters to the Pacific Ocean off California’s coast. El Nino is the periodic warming of the eastern and central Pacific Ocean. As Faiza Elmasry tells us, this phenomenon thrills scientists and gives anglers the chance of a once-in-a-lifetime big catch. Faith Lapidus narrates.

Video Terrorism in Many Forms Continues to Plague Africa

While the world's attention is on Paris in the wake of Friday night's deadly attacks, terrorism from various sides remains a looming threat in many African countries. Nigerian cities have been targeted this week by attacks many believe were staged by the violent Islamist group Boko Haram. In addition, residents in many regions are forced to flee their homes as they are terrorized by armed militias. Zlatica Hoke reports.

Video Study: Underage Marriage Rate Higher for Females in Pakistan

While attitudes about the societal role of females in Pakistan are evolving, research by child advocacy group Plan International suggests that underage marriage of girls remains a particularly big issue in the country. VOA’s Ayesha Tanzeem reports how such marriages leads to further social problems.

VOA Blogs