The eightigue could have an unexpected advantage: a reduction in the risk of Lung Cancer , according to two studies on mice 1 , 2 .

The results published as Preprints on the BiOrxiv server show specific genes that could contribute to the decreasing risk and reveal a surprising connection to Iron metabolism . The studies have not yet been examined by experts.

The results may appear contragituit: Cancer is a disease associated with aging , and the probability of many Cancer diagnoses reached its peak in a person's 60s or 70s. But then the rates of many of these cancer drop mysteriously.

"It is an observation that we have made for decades," says Ana Gomes, the aging and cancer at the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida, and is not involved in the proprints. "But we really couldn't explain why."

age accumulation

Cancer is caused by DNA mutations that accumulate over time . More years of life mean more opportunities to collect the constellation of mutations that are necessary to create Rogue cancer cells that grow uncontrollably. Immune responses that would once have been able to keep a tumor in check, can also be quieter with increasing age .

But the changes in the tissue that go hand in hand with aging can also discourage tumor growth by changing the environment in which cancer cells live. For example, older lungs tend to have more scar tissue than younger lungs. Lung cells are also less capable of regeneration and less resistant to the stress factors of unregulated growth. "The environment that you have at a older age is structurally and functional, a completely different environment than the one you have at a young age," says Gomes.

to learn more about how aging influences tumor growth, Emily Shuldiner, a cancer biologist at Stanford University in California, and her colleagues have studied mice who have a carcinogenic mutation that controlled the authors with a genetic switch 1 . The team switched on these mutated genes in the lungs of young and old mice and found that tumors were greater and more common in the younger mice than with the older mice.

The researchers also used CrisPR-CAS9-GENTechnik in maustumors to examine the effects of the inactivation of more than two dozen genes that normally suppress tumor growth. On average, switching off most of these genes increased the growth rate of tumors in mice of all ages, but there were more tumors, and they grew greater, with younger mice than in older mice. This suggests that a different process could work in older mice to suppress cancer.

iron handle on tumors

Another team under the direction of Xueqian Zhuang, a cancer biologist at the Memorial Sloan Kettering Cancer Center in New York City, found that aging has influenced the production of a protein called NUPR1-in mouse and human lung cells 2 . The cells then behaved as if they were iron arm, which restricted their capacity for quick growth that is a license plate of cancer.

In order to pursue this discovery, the Team Crispr-Cas9-Gentechnik used to inactivate the nupr 1 -Gen in older mice. The iron values ​​in the lungs of the animals rose and the mice became more susceptible to tumors, like their younger counterparts.

The authors also found that people over 80 years have more NUPR1 in their lung tissue than people under the age of 55, which indicates that mechanism could be preserved between mice and humans.

The stress of cancer

The results show that aging can influence the fitness of lung cancer cells in a way that prevents tumors, says Gomes. But there could be important differences of how tumors arise in humans and in these mice. In humans, cancer -causing mutations are usually gradually increasing, and the seeds of cancer can disappear for decades before a tumor can be detected. However, the tumors were initiated in the mice by suddenly switching on the cancer -causing gene when the mice were already old.

and results on lung cancer may not be transferred to cancer in other tissues, says Cecilia Radkiewicz, oncologist and crab epidemiologist at the Karolinska Institute in Stockholm. "It is quite different between different types of cancer because they have different biological drivers," she says.

Radkiewicz has found that in many types of cancer, the apparent decline in incidence in old age could be an artifact. When they examined how often tumors were found in autopsies, this decline often disappeared 3 . This indicates that the rates of different types of cancer often remain the same even in old age, she says, but cancer are simply diagnosed or reported less often in people over 75 years.

an exception, she adds, was lung cancer: its incidence actually decreased in older people, even if you take into account the autopso -sied data.

Overall, the results emphasize the importance of studies on cancer in old mice, says Zhuang. Such studies can be difficult, she says: It is expensive and time -consuming to breed mice into old age. But the results could show new possibilities for the treatment of cancer in old and young people as well as important goals for Raise Renerative Medicine

"People often think that aging is bad," says Dmitri Petrov, evolutionary biologist at Stanford University and author of the Preprint together with Shultiner. "But if this is correct, aging has an important role."