Cancer and aging – is everything not as we thought?

Professor James DeGregori from the University of Colorado Cancer Center in Denver analyzed the available scientific data and came to the conclusion that contradicts the generally accepted opinion that the risk of developing cancer in old age increases the accumulation of mutations that cause cell malignancy. He claims that the real reason is age-related changes in body tissues.

As one of the proofs, the author cites the fact that by the time growth stops in late adolescence, most of the mutations are already accumulating in the body, which will persist in it throughout later life. According to Gregory, if the critical point for increasing the risk of cancer was the accumulation of a certain number of mutations, the disease would develop mainly in 20-year-olds, since this age is characterized by the highest rate of accumulation of mutations.

The second evidence in favor of the new hypothesis is that even healthy tissues contain oncogenic mutations. In reality, the frequency of occurrence of such mutations is much higher than the frequency of occurrence of associated tumors. In other words, a greater number of mutations does not necessarily mean a greater likelihood of developing cancer either in elderly people or in specific tissues.

The two final proofs given by Gregory are rooted in the theory of evolution. Since the process of evolution went from unicellular short-lived life forms to multicellular organisms with a long lifespan, during this process the human body had to acquire a complex system that supports the functioning of tissues and prevents the development of diseases. However, the ability of the human body to protect itself from mutations is no better than the ability of unicellular yeast. If preventing mutations was the key to protecting against cancer, the human body would cope with this task much better.

And, finally, if oncogenes were such super-villains as modern theory describes them, their introduction into the genome of mouse stem cells would contribute to their survival. In reality, on the contrary, there is a tendency to selective death of oncogen carrier cells.

Based on all this, the author of the new hypothesis came to the conclusion that the reason for the increased risk of cancer in old age is not the accumulation of mutations, but the weakening of the effectiveness of the mechanisms that the young body uses to fight degenerating cells.

The functions of healthy cells are optimized for the conditions of healthy young tissues. Therefore, emerging oncogenic mutations weaken cells that quickly self-destruct, unable to withstand competition. However, in an aging organism, this balance is disturbed, and healthy cells lose their superiority over carriers of oncogenic mutations, which have an extensive arsenal of adaptations to changing conditions.
Article by J DeGregori Challenging the axiom: does the occurrence of oncogenic mutations truly limit cancer development with age? published in the journal Oncogene.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of Colorado Cancer Center:
Why cancer rate increases with age (it’s not what you think).

09.07.2012