Tumor Protein Induces Atrophy

Cancer is an umbrella term for an assortment of diseases stemming from abnormal cell growth, yet one symptom seen across many types of cancer is a chronic wasting away of the person’s muscle and fat tissue. This perilous atrophy, called cachexia, interferes with a patient’s ability to withstand challenging chemotherapy and radiological treatments and is responsible for 20% of cancer deaths. Two sets of researchers are now reporting that they’ve identified a tumor-secreted protein called ImpL2 that may be to blame for cancer-related cachexia (Dev. Cell 2015, DOI: 10.1016/j.devcel.2015.03.001 and 10.1016/j.devcel.2015.02.012). The teams, led by David Bilder of the University of California, Berkeley, and by Norbert Perrimon of Harvard Medical School, found that tumors release ImpL2 and that the protein prompts cancerous wasting—at least in fruit flies, although humans have an analogous protein. In fruit flies, ImpL2 leads to insulin resistance, which in turn leads to catastrophic weight loss. Curiously, tumor cells sidestep ImpL2’s effects and continue to grow abnormally. The researchers hope the discovery of ImpL2 could lead to new therapies to treat cachexia.