Smoke Exposure Rewires Lung Stem Cells to Shape Cancer Subtype
Using laboratory-grown lung organoids, researchers found that chronic cigarette smoke exposure changes the epigenetic state and gene activity of lung cells. When cancer-driving mutations such as KRAS activation or TP53 loss were added, only smoke-exposed organoids formed tumours after implantation into mice. The type of genetic alteration also influenced which non-small cell lung cancer subtype developed.
Researchers grew mouse lung organoids and kept them in cigarette smoke condensate for six months. This long exposure shifted epigenetic regulation and gene activity, dampened inflammation, immune signalling and cell-death pathways, and altered stem and differentiated cell populations.
Adding KRAS mutation or TP53 loss then produced tumours after implantation only in smoke-exposed organoids. KRAS-linked growths resembled lung adenocarcinoma; TP53-deficient ones resembled squamous cell carcinoma, apparently arising from bronchioalveolar or basal stem-cell states. Human organoid and tumour data showed similar signals, including lower ZBP1/interferon activity in KRAS tumours, though causation in people was not established.
People with long-term cigarette or secondhand smoke exposure may be most affected by this research. If smoke-induced cell changes help determine which lung cancer subtype emerges, future screening or treatment strategies could become more tailored. The work might also guide studies into epigenetic or immune-based therapies for tumours that resist current options, though clinical benefits remain uncertain and would require validation in people.