In addition, distal lung cells including alveolar epithelial type 2 cells are identified by SOX9 expression (Laughney et al., 2020), and SOX9 was shown to associate with POU class 2 homeobox 3 (POU2F3)-driven subtype of SCLC (Huang et al., 2018), which represents a subtype of SCLC lacking typical NE markers (Rudin et al., 2019). The gene discussed is POU2F3; the disease is small cell lung carcinoma.