This study aims to investigate the expression of neuronal transcription factor SOX11 in small-cell lung cancer (SCLC) and compare it with the expression of CD56 (nerve cell adhesion molecule), synaptophysin (Syn), chromogranin A (CgA), and thyroid transcription factor-1 (TTF-1) to explore the application value of SOX11 in the pathological diagnosis of SCLC. This evidence concerns the gene TTF1 and small cell lung carcinoma.