Insulinoma‐associated 1 (INSM1), a highly expressed gene in several SCLC tumors (Lan et al, 1994), which is used as a cytoplasmic marker for neuroendocrine differentiation of tumor cells (and indirectly in SCLC tumorigenesis), was also downregulated in the three cell lines. This evidence concerns the gene INSM1 and small cell lung carcinoma.