Obesity, alcoholism, and chronic hepatitis all increase the risk of getting liver cancer. These three health problems also increase cellular stress in the liver, but until now it has not been clear if there is a direct biological link between cellular stress and the development of liver cancer. In a new study, University of Iowa researchers have identified an unexpected molecular link between liver cancer, cellular stress, and these health problems.
The study, published recently in the journal PLOS Genetics, shows that a protein called CHOP, which had previously been thought to generally protect against cancer, actually promotes liver cancer in mice and may do the same in humans. CHOP is a transcription factor that is produced when cells experience certain kinds of stress. It is known to promote cell death (apoptosis).
Usually, factors that promote cell death protect against cancer by causing damaged cells to die. The study shows that, despite its role in cell death, CHOP is elevated in liver tumor cells in mice. Furthermore, mice without CHOP are partially protected from liver cancer, developing fewer and smaller tumors than the normal mice in response to liver cancer-causing drugs. The mice without CHOP also had less liver scarring and inflammation than mice with the protein. Tissue samples from human patients show that CHOP also is elevated in human liver tumors compared to surrounding non-tumor tissue from the same patients. Read the article.