Scientists at the University of Dundee in the UK discovered a link between an aging immune system and cancer development.
The study, published in the journal, Proceedings of the National Academy of Sciences, suggests that cancer risk increases with age due to an aging immune system. It has been established that our immune system becomes less effective as we get older, making us more vulnerable to disease.
The team which included researchers from the Institut Curie in France, Heriot-Watt University, and the University of Edinburgh, sifted through two million cancer cases with an age range between 18 and 70 years.
According to the study, men had a higher chance statistically than women to be diagnosed with cancer. The risk, however, started to increase across both groups when looking at older individuals. In addition to age, genetic predisposition, lifestyle and environmental factors also played a part in cancer diagnosis.
Researchers found that the immune system declines slower in women compared to men. This was linked to the thymus gland, which produces T cells that kill foreign or dysfunctional cells in the body. Despite the gland’s importance during our younger stage, it begins to shrink from the age of 1. The thymus gland loses half of its size every 16 years, reducing the number of produced T cells in the process.
To reach their conclusion, the team designed a mathematical model that predicted how cancer rates would increase if they were associated with a declining immune system. They then compared their findings with real-life data.
According to the study, this new model produced better results than the multiple mutation hypothesis, in which it is theorized that cancer is caused by a succession of gene mutations picked up over time.
“We believe that our findings are extremely relevant and show the need to take the immune syste, even more seriously in cancer research,” said Professor Clare BlackBurn, an expert in thymus biology at the University of Edinburgh.
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