What mechanisms drive brain metastases in patients with non-small cell lung cancer?
Brain metastases are a common and serious complication of non-small cell lung cancer (NSCLC). They occur when cancer cells from the lung travel to the brain and grow there. Several mechanisms drive this process, including changes in how tumor cells use energy, how they interact with the brain's immune environment, and specific molecular pathways that help them survive and grow in the brain. Understanding these mechanisms is key to developing better treatments.
What the research says
A 2025 study identified SEC61G as a key gene that is highly active in brain metastases from NSCLC 9. SEC61G helps cancer cells by stabilizing an enzyme called PGAM1, which boosts glycolysis (a way cells produce energy) 9. This metabolic reprogramming supports tumor growth in the brain. SEC61G also remodels the immune microenvironment, making it less hostile to cancer cells 9.
Another study found that in EGFR-mutant lung cancer, cancer cells with high levels of S100A9 can escape treatment with the drug osimertinib and initiate brain relapses 10. S100A9 activates the ALDH1A1-retinoic acid signaling pathway, which drives brain metastasis 10. Blocking this pathway with a pan-RAR antagonist reduced brain metastasis in models 10.
A systematic review describes that brain metastases involve blood-brain barrier disruption, formation of an immunosuppressive niche, and metabolic adaptation 5. Tumor cells co-opt neural signals and alter their metabolism to survive in the brain 5. Eosinophils in the tumor microenvironment can have dual roles, sometimes promoting anti-tumor immunity and sometimes helping tumors grow 8. Their role in brain metastases is still being studied.
Other research highlights that the tumor microenvironment in lung cancer is complex, with factors like oxidative stress, lipid metabolism, and epithelial-mesenchymal transition (EMT) playing roles 4. These processes can also influence how tumors spread to the brain.
What to ask your doctor
- Could my NSCLC tumor be tested for SEC61G or S100A9 levels to assess brain metastasis risk?
- Are there any treatments that target the SEC61G-PGAM1 or S100A9-ALDH1A1 pathways?
- How does the blood-brain barrier affect treatment options for brain metastases in my case?
- What is the role of immunotherapy for brain metastases given the immune microenvironment changes?
- Are there clinical trials for new drugs that prevent or treat brain metastases in NSCLC?
This question is drawn from common patient questions about Neurology and answered using cited medical research. We do not provide individualized advice.