The results of a new study may change the course of research on cancer prevention. Immune system may play a more important role in age-related cancer development than previously thought.
The urgency of the problem
Each year, more than 8 million people die from cancer worldwide. Although treatment is constantly improving, many questions remain unanswered. It is believed that cancer is caused by mutation of genes that accumulate over time. We know that certain factors can increase the rate at which they occur by genetic mutations and thus increase the risk of developing cancer. These factors include Smoking, alcohol consumption and obesity.
However, not all risk factors can be avoided; one of the major risk factors is aging.
Why aging increases cancer risk?
Recently, the research team gave an unexpected answer to this question.
There is reason to believe that over time the probability of mutations increases. So far, this was the standard explanation: the older you get, the more mutations you have, and the risk of cancer higher.
The hypothesis that the researchers set out to prove, was the fact that cancer risk increases with aging of the immune system. It is well known that with age the immune system becomes less efficient, making us more susceptible to disease.
Thymus or thymus is an organ of the immune system, which is involved in the development of T-cells. The decrease in the function of the immune system occurs due to the deterioration of the functions of the thymus.
Despite its importance, the thymus gland begins to decrease from 1 year, therefore, decreases the production of T-cells. The authors wondered whether such a reduction to play a role in the risk of cancer.
Materials and methods
The researchers studied data 2 million cases of cancer in people aged 18-70 years. Then they developed a mathematical model that predicted that the increase incidence of cancer, if it is associated with a decrease in the immune system. They compared their results with real data.
The scientific results
The researchers found that their model is more closely related to real data than the standard so-called hypothesis of multiple mutations.
Study leader Sam Palmer (Sam Palmer) explains:
“The hypothesis of immunosuppressively is that cancer cells constantly appearing in the body, but usually the immune system kills them before developing a new tumour. T cells are constantly searching for the cancer cells to destroy them. If they can’t find them quickly, or the immune system is weakened, populations of the cancer has a chance that increases with age, as the thymus is constantly declining”.
Age the risk of cancer in men increases more dramatically compared to women. Because the thymus decreases faster in men than in women, this may explain this difference that the theory of multiple mutation hypothesis cannot explain. Of course, this study was based on the mathematical model and hence needs to be tested in actual conditions.
Professor Clare Blackburn (Blackburn Clare) said: “In addition to mutations, we must also focus on how to improve the function of the thymus, possibly by transplantation or regeneration controlled, so we can increase the number of T-cells”.
These results open a new path for cancer researchers, and point out a vital step to new cancer prevention strategies.
The authors of another study suggest that normal weight women may have an increased risk of invasive breast cancer, if they have a high level of fat mass.