Even healthy tissues carry clusters of cells with mutations: study

(Ashley Yeager/ The Scientist) — Patches of healthy tissue can contain groups of cells with genetic mutations, researchers reported June 6 in Science. In the study, they analyzed 29 different tissue types taken from 488 people. The results showed that the majority of the healthy individuals had clumps of mutated cells in at least one tissue sample taken. Most of the mutations are harmless, but some are linked with cancer, a finding that could reveal how cancer takes hold in healthy tissue.

“We now appreciate that we are mosaics, and that a substantial number of cells in our body already carry cancer mutations,” Iñigo Martincorena, a geneticist at the Wellcome Sanger Institute in the UK who was not involved in the study, tells Nature. “These are the seeds of cancer.”

Previous research had shown that different types of tissues accumulate genetic alterations with age. Skin cells pick up mutations when they are exposed to the sun, and others collect DNA errors during cell division. In previous studies, scientists had documented widespread mutations in skin, esophagus, and blood cells separately. (…)

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