Ageing immune systems could have a major impact on cancer risk. CRM Group Leader Clare Blackburn and colleagues at the University of Dundee have found that the immune system may play a larger role in cancer development than originally thought.
Previously, researchers have understood multiple genetic mutations to be the root cause of cancer development.
The study, led by Professor Thea Newman along with Drs Sam Palmer and Luca Albergante, derived a mathematical model linking the age-related decline in production of a type of immune cell called T cells to the rising incidence of cancer with age. They found that their model predicted cancer incidence better than the previous view of accumulating mutations, when tested on data from 2 million cancer patients aged between 18 and 70. These findings suggest that the decline in the immune system with age and the risk of cancer are strongly related.
Thea Newman said,
“This is still very early days but if we are proven right then you could be talking about a whole new way to treat and prevent cancer”
T cells, a type of white blood cell that plays a vital role in our immune system, are made in a butterfly-shaped organ called the thymus, which is located just above the heart. These T-cells are responsible for getting rid of infected or damaged cells, including cells which could form cancers if they are not removed. However, the thymus halves in size every 16 years, and the production of T-cells decreases at a similar rate.
The new hypothesis that the ageing immune system is related to cancer risk matches perfectly with this understanding of the role of T-cells.
If multiple mutations were the sole cause of cancer, cancer risk would be expected to be equal in men and women. This is not the case. In fact, men experience a higher risk of cancer over their lifetimes and thymus function of males decreases faster. This new study provides an explanation for these observations.
Looking forward, investigations into boosting thymus function, through transplantation or controlled regeneration, could provide exciting new avenues for cancer prevention.
Clare Blackburn said,
“We believe that our findings are extremely relevant and show the need to take the immune system even more seriously in cancer research.
"In addition to mutations, this suggests we should also focus on how to boost thymus function in a controlled way, perhaps by transplantation or by controlled regeneration, so we can increase the number of T cells we are making. Of course, we also need to look at whether there may be unintended consequences of doing this, and how to minimise these if they occur.”
You can hear the Prof Thea Newman and Dr Sam Palmer describe the work in this video