Aging brings two opposing trends in cancer risk: first, the risk climbs in our 60s and 70s, as decades of genetic mutations build up in our bodies. B

The Risk of Cancer Fades as We Get Older, And We May Finally Know Why

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2024-12-22 16:30:04

Aging brings two opposing trends in cancer risk: first, the risk climbs in our 60s and 70s, as decades of genetic mutations build up in our bodies. But then, past the age of around 80, the risk drops again – and a new study may explain a key reason why.

The international team of scientists behind the study analyzed lung cancer in mice, tracking the behavior of alveolar type 2 (AT2) stem cells. These cells are crucial for lung regeneration, and are also where many lung cancers get started.

What emerged was higher levels of a protein called NUPR1 in the older mice. This caused cells to act as if they were deficient in iron, which in turn limited their regeneration rates – putting restrictions on both healthy growth and cancerous tumors.

"The aging cells actually have more iron, but for reasons we don't yet fully understand, they function like they don't have enough," says cancer biologist Xueqian Zhuang, from the Memorial Sloan Kettering Cancer Center (MSK) in New York.

The same processes were found to be happening in human cells too: more NUPR1 leads to a drop in the amount of iron available to cells. When NUPR1 was artificially lowered or iron was artificially increased, cell growth capabilities were boosted again.