Epidemiological studies indicate that being overweight or obese is associated with increased cancer risk. The most dramatic effect of obesity on cancer risk has been noted for a common form of liver cancer called hepatocellular carcinoma or HCC. Modeling the effect of obesity in mice, researchers at the University of California, San Diego School of Medicine have conclusively demonstrated that obesity is tumor-promoting and have obtained evidence that this effect depends on induction of low-grade, chronic inflammation. Their results, published January 22 by the journal Cell, may suggest novel therapy to prevent HCC development in obese men who suffer from chronic liver disease. Michael Karin, PhD, Distinguished Professor of Pharmacology in UCSD’s Laboratory of Gene Regulation and Signal Transduction, who led the study, found that obesity enhanced the development of HCC by stimulating the production of tumor-promoting cytokines – interleukin-6 (Il-6) and tumor necrosis factor (TNF) – that also cause chronic inflammation. Production of these signaling molecules, which are elevated in obese mice and in humans, causes inflammation of the liver and activation of a tumor-promoting transcription factor, a protein called STAT3. This protein in turn activates the formation and growth of liver cancer. The primary role […]