News / Health

Study Shows How Obesity Heightens Cancer Risk

Jessica Berman
In addition to being a known risk factor for diabetes, morbid obesity causes higher death rates in severely overweight cancer patients, regardless of their diet. Scientists have new evidence that excess fat stimulates and supports tumor growth.

Experts say up to 25 percent of cancer cases occur in morbidly obese individuals. And, for reasons not fully understood, tumors appear to be more aggressive and therapy less effective in patients with excess fat tissue.

But researchers at the University of Texas Health Science Center at Houston may have found the reason at the molecular level. They say expanding fat tissue cells emit hormones and growth factors, called adipokines, that promote the growth of new blood vessels which nourish and promote tumor growth.

“What we hypothesized is that cells from fat tissue become mobilized and travel to the site of the cancer and become a component of the tumor.  And then those trophic factors, the adipokines, start being secreted from within the tumor.  And because of that, they are more potent because they are in higher concentration inside the tumor,” said Mikhail Kolonin, an associate professor of stem-cell medicine at U.T. Health’s Institute for Molecular Medicine.

In experiments with obese and lean mice with tumors, Kolonin's team fed each group of rodents the same diet. The tumors inside the fat mice grew much faster.  In addition, investigators discovered the growths inside the obese mice drew in the circulating fat cells. While many of the cells turned into fat inside the tumor, others promoted formation of the blood vessel network, bringing it oxygen and nutrients.

Kolonin says significant weight loss can reduce the presence of these tumor-inducing fat cells.  And  he believes performing gastric bypass or bariatric surgery in morbidly obese individuals is a fast and effective way to reduce their risk of cancer.

“It is apparent from studies that have been done that treating obesity before cancer onset may be very beneficial because bariatric surgery, for instance, prevents not only the risk of developing diabetes but also developing certain cancers,” Kolonin said.

Such cancers, common in the morbidly obese, include colorectal cancer and cancer of the prostate in men and endometrial cancer, a type of uterine tumor, in women.

An article by Mikhail Kolonin and colleagues on the links between obesity and cancer is published in the journal Cancer Research.

You May Like

Video In US, Columbus Day Still Generates Controversy

Holiday marks date Columbus discovered Americas, but some are offended by legacy because he enslaved many natives he encountered More

Video Through Sports, Austria Tries to Give Migrants Traction

With 85,000 people expected to claim asylum in Austria this year, its government has made integration through joint physical activities a key objective More

Video Kickboxing Champion Shares Sport With Young Migrants

Pouring into Europe by hundreds of thousands, some migrants, especially youngsters, are finding sports a way to integrate into new host countries More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Amnesty Accuses Saudi Coalition of ‘War Crimes’ in Yemeni
Henry Ridgwell
October 12, 2015 4:03 PM
The human rights group Amnesty International has accused the Saudi-led coalition of war crimes in airstrikes against Houthi rebels in Yemen. Henry Ridgwell reports the group says hundreds of civilians have been killed in strikes on residential areas.

Video Amnesty Accuses Saudi Coalition of ‘War Crimes’ in Yemen

The human rights group Amnesty International has accused the Saudi-led coalition of war crimes in airstrikes against Houthi rebels in Yemen. Henry Ridgwell reports the group says hundreds of civilians have been killed in strikes on residential areas.

Video No Resolution in Sight to US House Speaker Drama

Uncertainty grips the U.S. Congress, where no consensus replacement has emerged to succeed Republican House Speaker John Boehner after his surprise resignation announcement. Half of Congress is effectively leaderless weeks before America risks defaulting on its national debt and enduring another partial government shutdown.

Video New Art Exhibit Focuses on Hope

Out of struggle and despair often comes hope. That idea is behind a new art exhibit at the American Visionary Art Museum in Baltimore, Maryland. "The Big Hope Show" features 25 artists, some of whom overcame trauma and loss. VOA’s Deborah Block reports.

Video Columbus Day Still Generates Controversy as US Holiday

The second Monday of October is Columbus Day in the United States, honoring explorer Christopher Columbus and his discovery of the Americas. The achievement is a source of pride for many, but for some the holiday is marked by controversy. Adrianna Zhang has more.

Video Anger Simmers as Turks Begin to Bury Blast Victims

The Turkish army carried out new air strikes on Kurdistan Workers Party (PKK) targets on Sunday, a day after the banned group announced a unilateral cease fire. The air raids apparently are in retaliation for the Saturday bombing in Turkey's capital Ankara that killed at least 95 people and wounded more than 200 others. But as Zlatica Hoke reports, there are suspicions that Islamic State is involved.

Video Bombings a Sign of Turkey’s Deep Troubles

Turkey has begun a three-day period of mourning following Saturday’s bomb attacks in the capital, Ankara, that killed nearly 100 people. With contentious parliamentary elections three weeks away, the attacks highlight the challenges Turkey is facing as it struggles with ethnic friction, an ongoing migrant crisis, and growing tensions with Russia. VOA Europe correspondent Luis Ramirez reports.

Video Afghanistan’s Progress Aided by US Academic Center

Recent combat in Afghanistan has shifted world attention back to the central Asian nation’s continuing civil war and economic challenges. But, while there are many vexing problems facing Afghanistan’s government and people, a group of academics in Omaha, Nebraska has kept a strong faith in the nation’s future through programs to improve education. VOA’s Greg Flakus has more from Omaha, Nebraska.

Video House Republicans in Chaos as Speaker Favorite Withdraws

The Republican widely expected to become the next speaker of the House of Representatives shocked his colleagues Thursday by announcing he was withdrawing his candidacy. The decision by Majority Leader Kevin McCarthy means the race to succeed retiring Speaker John Boehner is now wide open. VOA National Correspondent Jim Malone reports.

Video German, US Officials Investigate Volkswagen

German officials have taken steps to restore some of the reputation their car industry has lost after a recent Volkswagen diesel emissions scandal. Authorities have searched Volkswagen headquarters and other locations in an effort to identify the culprits in the creation of software that helps cheat on emission tests. Meanwhile, a group of lawmakers in Washington held a hearing to get to the bottom of the cheating strategy that was first discovered in the United States. Zlatica Hoke reports.

Video Why Are Gun Laws So Hard for Congress to Tackle?

Since taking office, President Barack Obama has spoken out or issued statements about 15 mass shootings. The most recent shooting, in which 10 people were killed at a community college, sparked outrage over the nation's gun laws. But changing those laws isn't as easy as many think. VOA's Carolyn Presutti reports.

Video In 'He Named Me Malala,' Guggenheim Finds Normal in Extraordinary

Davis Guggenheim’s documentary "He Named Me Malala" offers a probing look into the life of 18-year-old Malala Yousafsai, the Pakistani teenager who, in 2012, was shot in the head by the Taliban for standing up for her right to education in her hometown in Pakistan's Swat Valley. Guggenheim shows how, since then, Malala has become a symbol not as a victim of brutal violence, but as an advocate for girls’ education throughout the world. VOA’s Penelope Poulou has more.

Video Paintable Solar Cells May Someday Replace Silicon-Based Panels

Solar panels today are still factory-manufactured, with the use of some highly toxic substances such as cadmium chloride. But a researcher at St. Mary’s College, Maryland, says we are close to being able to create solar panels by painting them on a suitable surface, using nontoxic solutions. VOA’s George Putic reports.

VOA Blogs