Disclaimer: Discusses matters of obesity and cancer. As this is an early study, the writer encourages readers to look further into the matter for themselves at the link provided below.
Obesity, in many cases, plays a major role in the body's immune system and beyond. Recently, a study done by various Harvard educated researchers, (led by Dr. Arlene Sharpe) sought to further understand the relationship between T cells, a type of cell that can recognize and kill cancer cells, and a cancers tumor cells. Now how does obesity factor into this equation? Well, the abilities of T cells-as shown by a new, different study- are weakened by the presence of fat, which thus alters how these cells generate and use energy. As tumor cells rapidly consume surrounding nutrients and energy, leaving little available to nearby cells, the goal of the study done by Sharpe was to investigate the “Metabolic tug-of-war” occurring between the T-cell and the Tumor cell. Feeding a group of mice a high-fat diet for ten weeks, colorectal cancer cells were implanted into both this test group as well as a control group. What they found was that tumors had grown faster in the ‘obese’ mice than those of the control group. Upon a closer look, they discovered that, in and around the tumor, these T-cells were not functioning as they were in other parts of the mice's body. It appeared that, in the obese mice, the tumor cells had altered their existing metabolism to be able to derive nutrients from the surplus of fatty acids surrounding them, while the immune cells had made no such change. This left the immune cells without the proper nutrients and energy to effectively do their job, and allowed for the tumor to grow that much more efficiently. When relating this on a broader scale, the researchers took data from patients with colorectal cancer, and had found that signs of healthy T-cells were reduced in tumors from obese patients. However, as is with most scientific studies, these finding should be taken with a grain of salt, as many factors could play a role in the relationship between T cells and tumor cells, ranging from bacterial makeup to the food that people eat. Additionally, the impacts of obesity are likely to range from patient to patient, as well as from cancer to cancer. Various studies have shown that obesity may make immunotherapy in diseases such as kidney cancer less effective. But, on the other hand, obesity may actually help the odds of a response to an immune checkpoint inhibitor in diseases such as melanoma. Overall, as said by Kristine Willis, Ph.D., of NCI’s Division of Cancer Biology, “This [study] is really just scratching the surface of a very important aspect of cancer biology… It highlights the importance of a systems biology approach to cancer research: not just studying a single element in the body, but examining how all of the elements interact with each other”