SMARCA4‑deficient non‑small cell lung cancer with an EGFR mutation: A case report

Abstract

SWI/SNF‑related, matrix‑associated, actin‑depen‑ dent regulator of chromatin, subfamily a, member 4 (SMARCA4)‑deficient non‑small cell lung cancer (dNSCLC) is a rare malignant tumor that originates in the lungs. It occurs more frequently in male smokers, and the epidermal growth factor receptor (EGFR) gene is often mutation‑free. In the present study, the case of a 60‑year‑old, non‑smoking female patient diagnosed with SMARCA4‑dNSCLC is reported. Biopsy of the tumor showed solid flaky, nest‑like infiltrating growth. Immunohistochemistry revealed the following: SMARCA4/BRG1(‑), SMARCB1/INI‑1(+), cyto‑ keratin7 (+), cytokeratin 5.2 (+), CK5/6(+) and calretinin(+). The Ki‑67 positivity index was 75%, and the thyroid tran‑ scription factor‑1, NapsinA, p40, nuclear protein in testis, CD34, Sal‑like protein 4, SRY‑box transcription factor 2 and synaptophysin were negative. Molecular analysis showed mutations in both EGFR and TP53. The pathological diagnosis was SMARCA4‑dNSCLC with an EGFR gene mutation. The present case report could be used for broad‑ ening the pathological diagnosis of SMARCA4‑dNSCLC and for selecting appropriate treatment approaches.