Obesity Promotes Tumor Growth Regardless of Diet

"Tumor" technically means swelling.

Researchers may have discovered a new explanation as to why obese patients with cancer often have a poorer prognosis compared with those who are lean. The potential explanation is based on data reported in Cancer Research, a journal of the American Association for Cancer Research.

"Studies of the population have clearly established that there is a link between obesity and cancer incidence," said Mikhail Kolonin, Ph.D., associate professor at the Institute of Molecular Medicine at the University of Texas Health Science Center at Houston. "Moreover, for several cancers, obesity is associated with a poorer prognosis."

Kolonin and his colleagues evaluated how obesity promotes cancer progression. "Our earlier studies led us to hypothesize that fat tissue called white adipose tissue, which is the fat tissue that expands in individuals who are obese, is itself directly involved and that it is not just diet and lifestyle that are important," he said.

Their initial results confirmed this hypothesis: In obese and lean mice that ate the same diet, tumors grew much faster in obese mice than they did in lean mice. The researchers also observed that there were far more white adipose tissue cells (called adipose stromal cells) in obese mice than in lean mice and thus turned their focus on the role of these cells.

Rule of thumb: swollen people, more cancer.