The increased expression of ASCL1 in some SCLC tumors (relative to the expression of the other neuroendocrine transcription factors NEUROD1 and POU2F3) has since led to the identification of a separate SCLC subtype, SCLC-A which is discussed in greater detail in a later section of the article. The gene discussed is ASCL1; the disease is small cell lung carcinoma.