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New insights into aging and cancer
A recent study shows that cell division slows down significantly in old age. This finding provides far-reaching conclusions about the aging process and the course of cancer, because until now science has assumed that the cell proliferation rates remain the same for life.
Researchers at the Johns Hopkins Kimmel Cancer Center found in an analysis that the rate of cell division appears to slow significantly with age. The results of the study were recently published in the journal "Proceedings of the National Academy of Sciences" and are intended to help in the future to better understand processes of aging and their effects on the development of cancer.
False assumption over decades
Earlier research assumed that the development of cancer is favored by an accumulation of mutations and therefore the risk increases with increasing age. This presupposes that the speed of cell division remains the same. The Johns Hopkins research team has now investigated this connection and found that this assumption is incorrect. "Research in the past few decades assumes that such mutations will constantly accumulate over time," reports oncology professor Dr. Cristian Tomasetti from the study team. According to the study, this is not so - the number of mutations even decreases with advanced age.
Course of the study
The team analyzed tissue samples from biopsies of more than 300 patients using the latest computer technology. One group consisted of participants around the age of 20, and another group was around 80 on average. The researchers stained various markers of cell division with dyes in order to be able to document the growth rates.
Cell division slows down significantly
Their results showed that the cell division rates in the intestinal tissue in 80-year-olds decreased by about 40 percent compared to people aged 20 years. The division rate in the esophagus also slowed by an average of 25 percent. In the posterior tissue of the nose, the rate of division in older people even slowed by 83 percent.
The risk of cancer decreases again towards the end of life
According to the research team, the results have numerous implications for a better understanding of cancer and aging. For example, it has long been known that the frequency of most human cancers increases sharply with age. However, at the end of life, this risk decreases again for many types of cancer. A phenomenon that so far made no sense. "If the cell division rate decreases with age, the cells are likely to accumulate fewer carcinogenic mutations at the end of life," explains Tomasetti.
Further research needed
Why human cells slow their replication at the end of life is currently unknown and will form the basis for future studies. "The fact that human cells slow down their rate of division was not unexpected, but our study confirms it for the first time," summarizes the professor. This could have important implications for human health and future studies. (vb)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Graduate editor (FH) Volker Blasek
- Cristian Tomasetti, Justin Poling, Nicholas J. Roberts, et al .: Cell division rates decrease with age, providing a potential explanation for the age-dependent deceleration in cancer incidence, Proceedings of the National Academy of Sciences, 2019, pnas.org
- Johns Hopkins Medicine: Novel Study Documents Marked Slowdown of Cell Division Rates in Old Age (accessed: October 22, 2019), hopkinsmedicine.org