Importantly, the findings described above are in marked contrast to what occurs in SCLC, where Notch, likely as a developmental evolutionary reminiscence, plays a tumor suppressive role, as evidenced by the presence of inactivating mutations in Notch components in 25% of SCLC tumors and the high levels of both the non-canonical Notch inhibitor, Dlk1, and the neuroendocrine-oncogenic factor, and Notch negatively-regulated gene, Ascl1 [106]. This evidence concerns the gene ASCL1 and small cell lung carcinoma.