A new study has found that astronauts have a higher level of DNA mutations after space travel, which could be a sign of an increased risk of cancer. The main concern is with radiation, which occurs at higher levels above the Earth’s atmosphere. Exposure to excessive radiation is one of the known risk factors for cancer. Read on to find out what the study found, what cancerous processes might be involved, and what is now recommended for astronauts.
Fourteen astronauts from the Space Shuttle program participated in the study. They flew shuttle missions lasting an average of 12 days between 1998 and 2001. The median age of the astronauts was 44 years old. The researchers took samples of the astronauts’ whole blood twice – ten days before the flight and on the day of landing – and white blood cells that were only taken once, three days after landing. These samples were frozen at 112 degrees below zero for 20 years.
The researchers found that astronauts were more likely to have somatic mutations in their genes, compared to people who hadn’t been in space. Somatic mutations occur in DNA after conception and involve cells other than sperm or egg, meaning they are not passed on to offspring. Mutations identified in astronauts resulted in the overrepresentation of blood cells derived from a single clone, a process called clonal hematopoiesis. This process is the cause of several types of blood cancer, including chronic myeloid leukemia.
“Astronauts work in an extreme environment where many factors can lead to somatic mutations, the most important space radiation, which means there is a risk that these mutations will turn into clonal hematopoiesis,” said David Goukassian, author principal of the study and professor of cardiology. at Icahn Mount Sinai in New York, in a statement. He added: “Given the growing interest in commercial spaceflight and deep space exploration, and the potential health risks from exposure to various harmful factors associated with exploration space missions repeated or long-lasting, like a trip to Mars, we decided to explore, retrospectively, somatic mutation.”
Using DNA sequencing and bioinformatics analysis, researchers identified 34 mutations in 17 genes in astronauts. The most common mutations were in TP3, a gene that produces a tumor suppressor protein, and DNMT3A, one of the genes most likely to mutate in acute myeloid leukemia. Although these mutations were high, they did not exceed two percent, an official threshold for concern. But the researchers had recommendations for NASA for the future. “The presence of these mutations does not necessarily mean that astronauts will develop cardiovascular disease or cancer, but there is a risk that over time this may occur due to continued and prolonged exposure to the extreme environment. deep space,” Goukassian said.
The researchers said NASA and its medical teams should screen astronauts for somatic mutations and clonal changes every three to five years, even after they retire. “What is important now is to conduct well-controlled retrospective and prospective longitudinal studies involving large numbers of astronauts to see how this risk changes with continued exposure, and then compare this data to their clinical symptoms. , imaging and lab results,” Goukassian said. “This will allow us to make informed predictions about which individuals are most likely to develop disease based on the phenomena we observe and open the door to individualized precision medicine approaches for early intervention and prevention.”
Other studies have focused on the cancer risk of astronauts. A 2019 study of more than 300 American astronauts and more than 100 Russian cosmonauts found no increased relative cancer risk compared to the general population — in fact, their cancer risk was lower than expected.