Indoor radon exposure increases tumor gene mutation in non-smoking patients with lung cancer, according to a study led by Professor Lim Sun-min at CHA Bundang Medical Center’s Medical Oncology Division.
The study, reportedly the first to confirm that radon exposure was involved in gene mutation in lung cancer, was published in the online edition of international journal Lung Cancer.
|Professor Lim Sun-min of the Medical Oncology Division of the Internal Medicine Department at CHA Bundang Medical Center|
The study results showed that patients with high exposure to residential radon (over 48 Bq/㎥) had 2.34 more tumor mutation burden (TMB) per 1MB on average than the low-radon group. The high-radon group also had an error in the DNA damage repair system and significant DNA damage caused by radon.
In other words, the study revealed that non-smoking lung cancer patients exposed to a high level of radon have a poor prognosis and a high chance of recurrence due to the increased tumor mutation.
Lim’s research team surveyed 439 I-IIIA non-smoking patients diagnosed with lung adenocarcinoma from October 2015 to May 2016 and measured the levels of radon in their homes.
The team divided the patients into two groups – one with high radon exceeding 48 Bq/㎥ and the other with low radon below 48 Bq/㎥. They then compared tumor genes and analyzed the sequencing of tumor mutation in 41 patients who agreed on the gene analysis.
Radon, which emits radiation, is a Group 1 carcinogen that can be easily exposed in daily life. Group 1 means the agent is carcinogenic to humans. Radon can cause lung cancer in non-smokers, and the World Health Organization (WHO) estimates that 3 to 14 percent of all lung cancer patients suffer from the disease because of radon.
“This study confirms that the daily radon exposure increases tumor mutation and malignancy in lung cancer patients and makes it difficult to treat them,” Lim said. “As we confirmed the mutant genes caused by radon exposure, this will help in developing customized, targeted therapies in the future.”
Yonsei University College of Medicine Professor Kim Hye-ryun and Yonsei University Wonju College of Medicine Professor Kang Dae-ryong also participated in the joint study.