A high-fat diet allows cancer cells to outcompete immune cells for fuel, impairing immune function and accelerating tumour growth. Cancer cells do so by rewiring their metabolisms to increase fat consumption. Blocking this rewiring enhances anti-tumour immunity.
Obesity has been linked to increased risk for over a dozen different types of cancer, as well as worse prognosis and survival. Over the years, scientists have identified obesity-related processes that drive tumour growth, such as metabolic changes and chronic inflammation.
Now, new research shows that a high-fat diet reduces the numbers and antitumor activity of CD8+ T cells, a critical type of immune cell, inside tumours. This occurs because cancer cells reprogram their metabolism in response to increased fat availability to better gobble up energy-rich fat molecules, depriving T cells of fuel and accelerating tumour growth.
Researchers found that tumours grew much more rapidly in animals on high-fat diets compared to those on normal diets. But this occurred only in cancer types that are immunogenic, which can contain high numbers of immune cells; are more easily recognized by the immune system, and are more likely to provoke an immune response.
Experiments revealed that diet-related differences in tumour growth depended specifically on the activity of CD8+ T cells, immune cells that can target and kill cancer cells.
Source: Harvard Medical School