A new link between cancer and aging?
A new study in 2022 revealed a thought-provoking relationship between how long animals live and how quickly their genetic codes mutate.
Cancer is a product of time and mutation, and so researchers have investigated its onset and impact in 16 unique mammals. A new perspective on DNA mutation expands our understanding of aging The development of cancer – and how we can control it.
Mutations, aging and cancer: a primer
Cancer is the uncontrolled growth of cells. It’s not a pathogen infecting the body, but the body’s natural process has gone wrong.
Cells are dividing and multiplying in our bodies all the time. Sometimes during DNA Replication, small errors (called mutations) appear randomly within the genetic code. Our bodies have mechanisms to correct these mistakes, and for many of our young people we stay strong and healthy as a result of these corrective actions.
However, this protection weakens as we age. The likelihood of developing cancer increases when mutations bypass our defenses and continue to multiply. The longer we live, the more mutations we carry, and the more likely it is that they will manifest in cancer.
Because mutations can occur randomly, biologists expect that larger life forms (those with more cells) have higher chances of developing cancer than smaller life forms.
Oddly enough, there is no correlation.
It’s one of the biggest mysteries in biology about why large creatures like whales or elephants rarely get cancer. This is called Bito’s paradox. Even stranger, some smaller creatures, such as the naked mole rat, are completely cancer-resistant.
This phenomenon is prompting researchers to look into the genetics of naked mole rats and whales. And while we have discovered that specific genetic rewards (such as additional tumor suppressor genes) benefit these organisms, the pattern of cancer rates in all other species remains poorly understood.
Cancer may be closely related to lifespan
Researchers at the Wellcome Sanger Institute Report The first study looks at how mutation rates compare with an animal’s age.
Mutation rates are simply the speed at which a species generates mutations. Mammals with shorter lifespans have very fast mutation rates. The mouse undergoes nearly 800 mutations in each of its four short years on Earth. Mammals with longer lifespans have average mutation rates that are much slower. In humans (average age approximately 84 years), it relates to fewer than 50 mutations per year.
The study also compares the number of mutations at the time of death with other traits, such as body mass and age. For example, a giraffe contains approximately 40,000 times more cells than a mouse. Or a human lives 90 times longer than a mouse. What surprised the researchers was that the number of mutations at the time of death differed only threefold.
This small differentiation indicates that there may be a total number of mutations that a species can collect before it dies. Because mammals have reached this number at different speeds, finding ways to control the rate of mutation may help impede the development of cancer, retard aging, and extend life.
The future of cancer research
The findings in this study raise new questions for understanding cancer.
The assertion that mutation rate and lifespan are closely related to needs compared to life forms that go beyond mammals, such as fish, birds, and even plants.
It will also be necessary to understand the factors that control mutation rates. The answer likely lies in the complexities of DNA. Geneticists and oncologists continue to investigate genetic curiosities such as tumor suppressor genes and how they may affect mutation rates.
Aging is likely to be a confluence of many issues, such as epigenetic changes or telomere shortening, but if there are mutations, there may be hopes of slowing – or even reversing – genetic damage.
Although only a first step, linking mutation rates to age is a reformulation of our understanding of cancer development, and may open doors for new strategies and therapies to treat cancer or to tame a number of health concerns that come with aging.