Who conducted the study?
Dr. Chengfei Jian from Nanjing University, China, led the study. Thirdhand Smoke Consortium researchers were also involved, including Drs. Jian-Hua Mao, Lara Gundel, and Antoine Snijders from the Lawrence Berkeley National Laboratory and Drs. Suzaynn Schick and Peyton Jacob III from the University of California, San Francisco. Additional researchers from these three institutions, and the Chinese Academy of Science contributed to the study as well.
When did they publish it?
The study was published in September 2024 in the Environment International journal.
Where did they do it?
The scientists did this research at the Lawrence Berkeley National Laboratory in California and Nanjing University in China.
How did they do it?
The researchers exposed mice to thirdhand smoke-polluted clothes to investigate how stomach tumors developed. They also exposed human and mouse cells to thirdhand smoke to investigate how exposed cells change to form tumors. Dr. Jian-Hua Mao said the research team picked a specific type of mouse, called collaborative cross (CC) strain, for the study because they are “very susceptible to stomach cancers.” The researchers also measured how thirdhand smoke exposure impacted the likelihood of overall survival from stomach cancer using human cells from a global database of cell samples designated for cancer research.
What did they find?
The researchers found that mice exposed to thirdhand smoke had more tumors than mice that were not exposed. They also found that both human and mouse cells exposed to thirdhand smoke were more likely to change and form tumors than cells that were not exposed. The researchers found that the cells that had thirdhand smoke exposure had a worse chance of overall survival than those that had no exposure. These results offer insight into how thirdhand smoke exposure influences how cancer starts in people exposed to thirdhand smoke.
“From the new study, we find that thirdhand smoke is a promoter of cancer,” Mao said, explaining that cancer has two stages: (1) initiation, when the first cancer cells form, and (2) promotion, when the cancer cells form a tumor. “Promotion can result sometimes from inflammation. Thirdhand smoke exposure may cause inflammation in the tissues and subsequently promote cells to become tumors.”
Why is this study important?
Learning that thirdhand smoke exposure is involved in cancer promotion gives researchers a better understanding of how thirdhand smoke influences cancer. This knowledge may help scientists develop more effective treatments.
In addition, many people know that smoking and secondhand smoke exposure are related to cancer, but not everyone considers the risk of thirdhand smoke exposure. This study highlights the need to reduce thirdhand smoke exposure — not just first- and secondhand smoke exposure — to protect ourselves and others from an increased risk of stomach cancer. Learn how to reduce your thirdhand smoke exposure on the Thirdhand Smoke Resource Center website.
Click here to read the research study.
