Purpose To investigate the clinical pathologic features of five SMARCA4-deficient non-small lung cancers(SMARCA4-dNSCLCs).Methods Five cases of SMARCA4-dNSCLC was underwent by HE,immunohistochemical staining,and molecular detection,analyzed their clinicopathological char-acteristics and reviewed relevant literatures.Results All 5 ca-ses were male,and mean age was 66 years.Five patients had a history of smoking,three patients were treated with cough and blood in sputum as the first symptom,one was treated with a history of pulmonary tuberculosis combined with limb mobility disorder,and one was diagnosed with pulmonary nodules by physical examination.Under microscopic observation,tumor cells were poorly differentiated,with solid nest sheet distribu-tion,some with glandular structure,tumor cells had abundant e-osinophilic or transparent cytoplasm,vacuolar nuclear chroma-tin,nucleoli was visible,and nuclear mitosis was common.In-flammatory cell infiltration and sheet of necrosis were seen in the stroma.Immunohistochemical staining showed 5/5 diffuse ex-pression of CK(AE1/AE3)and CK7,5/5 loss expression of BRG1,1/5 diffuse expression of p40 and CK5/6,and Ki67 proliferating index ranged from 20％to 90％.FISH tests showed that 4/4 SMARCA4 genes missed.Five patients were followed up for 2-15 months,3 patients died and 2 patients survived.Conclusions SMARCA4-dNSCLC can have extensive morphologi-cal features,high degree of malignancy,and complicated treat-ment.BRG1 deficiency is helpful for diagnosis.Deepening the understanding of SMARCA4-dNSCLC can help the clinical cor-rect choice of treatment strategies and accurately evaluate patient prognosis.