The gene SMARCA4 on chromosome 19q13 encodes the BRG1 protein, a component of the SWI/SNF chromatin remodeling complex, pivotal in tumorigenesis and progression.[1] Representing about 8% to 11% of lung cancers, SMARCA4-deficient NSCLC exhibits high malignancy, aggressive behavior, and poor prognosis, generally demonstrating suboptimal responses to cytotoxic chemotherapy.[2] Rarely do these NSCLCs harbor common oncogenic driver mutations such as EGFR, ALK, and ROS1, and no standardized treatment protocols exist for this subtype. The gene discussed is SMARCA4; the disease is lung cancer.