Title: The Surprising Twist in Cancer Risk: Why It Drops After Age 80
Article:
As we age, the risk of cancer increases, with decades of genetic mutations accumulating in our bodies. However, a recent study published in Nature has shed light on an intriguing phenomenon: after the age of 80, the risk of cancer starts to decrease. Scientists have now uncovered the reason behind this unexpected trend.
An international team of researchers focused on lung cancer in mice to unravel this mystery. They zeroed in on alveolar type 2 (AT2) stem cells, which are crucial for lung regeneration and often serve as the starting point for lung cancer.
The Role of NUPR1 Protein
The study revealed that older mice had higher levels of a protein called NUPR1. This protein caused cells to behave as if they were deficient in iron, slowing down their regenerative capacity. Consequently, both healthy cell growth and tumor formation were delayed. "Aging cells paradoxically have more iron, but for reasons we don’t fully understand, they function as if they don’t have enough," explains cancer biologist Xueqian Zhuang from the Memorial Sloan Kettering Cancer Center (MSK) in New York. "Aging cells lose their ability to renew and thus to exhibit the uncontrolled growth that characterizes cancer."
Similar processes were observed in human cells: higher NUPR1 levels led to reduced iron availability for cells. When NUPR1 was artificially lowered or iron levels were increased, cell growth capacity was restored. This discovery opens up potential avenues for developing treatments targeting iron metabolism, particularly in older adults. It could also potentially aid in restoring lung capacity in individuals still recovering from COVID-19.
Implications for Ferroptosis-Based Cancer Therapies
The findings also have implications for cancer therapies based on a type of cell death called ferroptosis, which is activated by iron. Ferroptosis was found to occur less frequently in older cells due to their iron deficiency. This could make older cells more resistant to ferroptosis-based cancer therapies currently under development. The earlier such treatments are administered, the more effective they may be.
"Our data suggest that the things that happen when we’re young are probably much more dangerous than the things that happen later in life," says cancer biologist Tuomas Tammela from MSK. "Encouraging young people to avoid smoking, unprotected sun exposure, and other clear carcinogenic factors may be even more important than we thought."
Further Research Needed
While more research is needed to understand the effects of NUPR1 and its relationship with stem cell function, both in healthy regeneration and tumor growth, these findings are significant in the fight against cancer at every stage of life. As with all cancer treatments, multiple factors must be considered, including the type and stage of cancer, other medical conditions, and, as this new study highlights, the age of the patient. The more personalized these treatments can be, the more effective they will be. However, there is still much to learn about how aging alters the biology of cancer, concludes Zhuang.
