Furthermore, they found a significant association between EGFR mutation status in plasma cfDNA and the presence of brain metastasis in 311 treatment-naive stage IV non-small cell lung cancer (NSCLC) patients, with an adjusted odds ratio of 2.73 (95% CI 1.39–5.36; p = 0.003). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.