Obesity Found to Accelerate Growth of Cancer Cells

Obesity has been linked to various types of cancers. Although cancer-related indicators such as metabolic changes and chronic inflammation are often seen in obese individuals, scientists have not pinpointed exactly why they are more prone to cancer. A recent study from Harvard Medical School presents a possible explanation, finding that diets high in fat allow cancer cells to outcompete tumor-killing immune cells in a battle for energy. 

A high-fat diet reduces the number and activity of CD8+ T-cells, which are critical immune cells inside of tumors. Cancer cells can actually reprogram their metabolism when more fat is available so they can better absorb the energy-rich fat molecules. This deprives T-cells of fuel, and tumor growth is accelerated. 

Using mice studies, researchers found that tumors grew quicker in animals on high-fat diets compared to those on normal diets. It was also discovered that immune cells divided more slowly and were less robust in the tumor microenvironment. When isolated, the immune cells exhibited normal activity, suggesting that the tumor impaired the cells’ function.

A surprising discovery was made amid the study. Although the entire body of the obese mice was enriched with fat, the area surrounding the tumor was depleted of key free fatty acids, which are a major source of cellular fuel. With this information, scientists were able to create a comprehensive profile of the different cell types in tumors under normal and high-fat-diet conditions. The researchers uncovered evidence proving cancer cells adapted in response to changes in fat availability, leaving T-cells starved of this essential fuel.

According to the Harvard scientists, the study serves as a foundation for further research to better understand how obesity affects cancer and the impact of patient metabolism on therapeutic outcomes. Their discoveries open the door for the exploration of new ways to use cancer immunotherapies and combination therapies.