by Air pollution was associated with a number of lung cancer DNA mutations, in a study of people in whom the disease was diagnosed, even though they have never smoked tobacco.
The results of an investigation of cancer patients around the world explain why those who have never smoked have an increasing proportion of people who develop the cancer, a trend that the researchers call “urgent and growing global problem”.
Prof. Ludmil Alexandrov, senior author of the study of the University of California in San Diego, said that the researchers had observed the “problematic trend”, but did not understand the cause.
“Our research shows that air pollution is strongly associated with the same types of DNA mutations that we typically associate with smoking,” he said.
The scientists analyzed the entire genetic code of pulmonary tumors, which were never removed in Europe, North America, Africa and Asia as part of the Sherlock-Lung study. They found that the higher the air pollution in a region, the more cancer and cancer -promoting mutations were available.
Fine-particular air pollution was particularly associated with mutations in the TP53 gene. These were previously associated with tobacco smoking.
People who were exposed to greater air pollution also had shorter telomeres, protective DNA strands at the ends of chromosomes, which are often compared to the caps at laces. The early shortening of telomeres is a sign of faster cell division, a license plate of cancer.
“This is an urgent and growing global problem that we understand,” said Dr. Maria Teresa Landi, epidemiologist at the study at the US National Cancer Institute in Maryland.
When smoking in many parts of the world, including Great Britain and the USA, people who have never smoked are a larger proportion of lung cancer patients. Current estimates suggest that 10-25% of lung cancer are diagnosed in this group. Almost all of these types of cancer are a form known as adenocarcinoma.
Lung cancer remains the most common cause of cancer -related death worldwide. Every year around 2.5 m new cases are diagnosed worldwide. In China, more than a million of deaths occur where smoking, air pollution and other environmental pollution are factors.
The latest studies have shown that the highest adenocarcinoma rates that are due to air pollution were in East Asia. While the cases in Great Britain were much lower, they were still more than 1,100 new diagnoses per year, as scientists found.
The latest works published in Nature identified only a slight increase in carcinogenic mutations in humans that are exposed to tobacco smoke made of used tobacco.
However, the study highlighted a significant risk of certain Chinese herbal medication, which contain aristolochic acid. Signature mutations associated with the herbal medication were almost exclusively observed in never smokers from Taiwan.
Another mysterious mutation signature was in people who had never smoked, but not those who did it and were now the focus of the “intensive investigation,” said Landi.
