In addition, tuft cell-like SCLC, LCNEC, and SQCC exhibited “lineage ambiguity”, namely with expressions of NCAM1 (NECs > SQCC) and KRT5 (SQCC > NECs) and infrequent expression of most neuroendocrine markers (Fig. 5D). The gene discussed is KRT5; the disease is large cell neuroendocrine carcinoma.