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

Turkey's Controversial Reform Bill Giving Investors Jitters

Homeland security reform bill will give police new powers in search, seizure, detention and arrests, while restricting the rights of suspects, their attorneys More

Audio Slideshow In Kenyan Prison, Good Grades Are Path to Freedom

Some inmates who get high marks could see their sentences commuted to non-custodial status More

'Rumble in the Jungle' Turns 40

'The Champ' knocked Foreman out to regain crown he had lost 7 years earlier when US government accused him of draft-dodging and boxing officials revoked his license More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Victorious Secularists Face Challenge to Form Government in Tunisiai
X
Henry Ridgwell
October 30, 2014 11:39 PM
Official results from Tunisia show the Islamist Ennahda party has failed to win the second free election since the so-called "Arab Spring" uprising in 2011. Ennahda, which handed power to a government of technocrats pending the elections, lost out to the secular party Nidaa Tounes. Henry Ridgwell reports from London that the relatively peaceful poll offers some hope in a volatile region.
Video

Video Victorious Secularists Face Challenge to Form Government in Tunisia

Official results from Tunisia show the Islamist Ennahda party has failed to win the second free election since the so-called "Arab Spring" uprising in 2011. Ennahda, which handed power to a government of technocrats pending the elections, lost out to the secular party Nidaa Tounes. Henry Ridgwell reports from London that the relatively peaceful poll offers some hope in a volatile region.
Video

Video Africa Tells its Story Through Fashion

In Africa, Fashion Week is a riot of colors, shapes, patterns and fabrics - against the backdrop of its ongoing struggle between nature and its fast-growing urban edge. How do these ideas translate into needle and thread? VOA’s Anita Powell visited this year’s Mercedes Benz Fashion Week Africa in Johannesburg to find out.
Video

Video Smugglers Offer Cheap Passage From Turkey to Syria

Smugglers in Turkey offer a relatively cheap passage across the border into Syria. Ankara has stepped up efforts to stem the flow of foreign fighters who want to join Islamic State militants fighting for control of the Syrian border city of Kobani. But porous borders and border guards who can be bribed make illegal border crossings quite easy. Zlatica Hoke has more.
Video

Video China Political Meeting Seeks to Improve Rule of Law

China’s communist leaders will host a top level political meeting this week, called the Fourth Plenum, and for the first time in the party’s history, rule of law will be a key item on the agenda. Analysts and Chinese media reports say the meetings could see the approval of long-awaited measures aimed at giving courts more independence and include steps to enhance an already aggressive and high-reaching anti-corruption drive. VOA’s Bill Ide has more from Beijing.
Video

Video After Decades of Pressure, Luxembourg Drops Bank Secrecy Rules

European Union finance ministers have reached a breakthrough agreement that will make it more difficult for tax cheats to hide their money. The new legislation, which had been blocked for years by countries with a reputation as tax havens, was approved last week after Luxembourg and Austria agreed to lift their vetoes. But as Mil Arcega reports, it doesn’t mean tax cheats have run out of places to keep their money hidden.
Video

Video Kobani Refugees Welcome, Turkey Criticizes, US Airdrop

Residents of Kobani in northern Syria have welcomed the airdrop of weapons, ammunition and medicine to Kurdish militia who are resisting the seizure of their city by Islamic State militants. The Turkish government, however, has criticized the operation. VOA’s Scott Bobb reports from southeastern Turkey, across the border from Kobani.

All About America

AppleAndroid