One study selected 68 patients with brain metastases from different primary cancer types, including 10 lung cancer patients, and evaluated the expression and clinical relevance of CAF-related biomarkers in brain metastases (BM), and showed that PDGFR-β and α-SMA were highly expressed in patients who had received chemotherapy or radiotherapy for their primary cancers, and that they were associated with a poor prognosis and recurrence in BM patients [188]. This evidence concerns the gene PDGFRB and lung cancer.