Claire L. McIntyre, PhD, Postdoctoral Fellow Brigham & Women's Hospital/Harvard Medical School Obesity is predicted to overtake smoking as the leading preventable cause of cancer. Yet a recent survey found that 85% of the public did not know obesity is linked to cancer, even when prompted. Communication of this important message needs to be improved. To fully explain the risks to patients, we need to better understand how obesity causes cancer. We know obesity can increase cancer growth and weaken tumor-killing immune cells. However, we do not fully understand which effects are caused by obesity and which are caused by diet. Using mouse models, Dr. McIntyre found consuming animal fat increases tumor growth and reduces anti-tumor immune cells. Whereas plant fats have no effect on tumor growth, despite mice being obese. This tells us that weight gain alone is not the only important factor, but that the type of fat consumed can promote cancer. Unlike plant fats, animal fats contain cholesterol. Dr. McIntyre predicts that eating combined high fat with high cholesterol drives cancer cell growth and reduces tumor-killing immune cells. To test this, she will feed a diet high in fat alone or with added cholesterol. She will measure tumor growth, changes in nutrients, and study pathways changed in cancer cells and immune cells. Dr. McIntyre hopes to identify what in the diet increases tumor growth and how it affects cancer and immune cells. This will uncover novel ways to use drugs to both halt tumor growth and restore anti-tumor immune cells. This research may also enable new approaches for the prevention or treatment of cancer through diet. Projects and Grants Investigating the mechanism underlying the consumption of animal fats and enhanced tumor growth. Brigham and Women’s Hospital / Harvard Medical School | All Cancers | 2022 | Lydia Lynch, Ph.D.