Scientists from Cancer Research UK and Memorial Sloan Kettering Cancer Centre in New York, USA have discovered a cancer treatment that can identify patients who are more likely to respond to cancer drugs.
A study uses tests for changes in the DNA (mutations) of cell components called mitochondria called mitochondrial DNA mutations (mtDNA). These mitochondrial DNA mutations can be used to identify patients who could benefit the most from immunotherapy (treatments that stimulate the body’s immune system to attack cancer cells). Mitochondria are the energy factories in all living cells.
Mitochondrial DNA mutations are found in up to half of all cancers, and can cause the mitochondria to not work properly. This affects the amount of a substance called adenosine triphosphate (ATP) in the tumour cells (the source of energy for the cells) as well as other processes in the cells.
The researchers found that tumours with high levels of mitochondrial DNA mutations were up to two and a half times more likely to respond to treatment with the immunotherapy, nivolumab, which works by releasing the brakes on the immune system to allow the immune system to attack cancer cells. Nivolumab is currently used to treat several different cancers, including kidney cancer, melanoma, lung cancer, liver cancer and bowel cancer.
The researchers suggest that by routinely testing for mitochondrial DNA mutations, this could help doctors identify which patients will benefit most from immunotherapy before starting treatment.
Also, the findings from the study suggest that combining treatments that mimic the effect of mitochondrial DNA mutations with immunotherapy could make treatment-resistant cancers sensitive to immunotherapy, increasing the chances of successful treatment.
This discovery is currently being developed in clinical trials.