Why Our Cancer Risk Increases with Age: Scientists Hope for New Treatments
As the world grapples with the news of King Charles’ cancer diagnosis, experts are taking the opportunity to shed light on the increased cancer risk that older individuals face. It is a well-known fact that as we age, our risk of developing cancer also increases. The average age of cancer onset is 66, and more than half of all new UK cancer cases are in individuals aged 70 and older, according to the US National Cancer Institute.
There are several reasons why our cancer risk rises as we get older. One of the simplest explanations is that over time, our cells accumulate more damage to their DNA. This damage can be caused by various factors such as exposure to UV rays, chronic inflammation, environmental toxins, alcohol consumption, smoking, and microbial infections. As we age, our cells become less efficient at repairing this damage, leading to an accumulation of DNA mutations in a tissue-specific manner. The more mutations that build up in our bodies, the greater the risk of uncontrolled cell division, or cancer.
Richard Siow, director of ageing research at King’s College London, explains that the repair mechanisms that prevent the onset of cancer-related changes decline as we age. The balances that maintain normal cellular function also go into decline as we grow older. Additionally, studies have shown that accumulating mutations impair the ability of immune cells to suppress and destroy cancer cells. One particular molecular pathway, known as p53, which is involved in suppressing tumors, becomes less effective with age due to mutations in the p53 gene.
Masashi Narita, a researcher at the University of Cambridge, has been studying cancer-causing gene mutations that become more common with age. By introducing these mutations into adult animals, Narita and his team have discovered that it triggers a rise in cellular senescence. Senescent cells are old and damaged cells that cease to divide and grow. An excessive accumulation of senescent cells can lead to chronic inflammation, causing further damage and increasing susceptibility to cancer.
However, these processes are just a fraction of the ways in which aging affects cancer risk. Luca Magnani, an epigeneticist at the Institute of Cancer Research in the UK, suggests that individual cells might lose their memory over time, just as human memory declines with age. This loss of memory could cause cells to proliferate even when they are not supposed to, potentially leading to breast cancer and other age-related cancers.
Another theory is that over a lifetime, the genome becomes less stable at transmitting information due to epigenetic changes or genetic modifications that impact gene activity without altering the DNA sequence. This increased noise and randomness in transmitting information can lead to changes that are carcinogenic.
While these theories shed light on the link between aging and cancer, they also offer hope for new treatments. Scientists are actively developing small molecules that aim to restore the normal tumor-suppressing functions of the p53 pathway. Additionally, researchers are exploring the use of senolytics, which selectively kill and remove senescent cells without damaging healthy tissue. Early-stage clinical trials are currently underway to test the efficacy of these treatments.
The ultimate goal is to reverse age-related changes and boost a person’s health-span, which refers to the number of years a person is healthy. By understanding how epigenetics contribute to increased noise and randomness, scientists hope to find ways to reverse these changes and develop effective treatments for age-related cancers.
The potential impact of these new treatment options is significant. Not only could they improve individual health, but they could also reduce the healthcare economic burden associated with an aging population living longer with disease. As research progresses, there is hope that new treatments will emerge, offering a ray of hope for those facing an increased cancer risk as they age.
If you enjoyed this article, be sure to sign up for The Essential List newsletter, a curated selection of features, videos, and can’t-miss news delivered to your inbox every Friday. Join the one million Future fans by liking us on Facebook or following us on Twitter or Instagram.
