RET and small cell lung carcinoma: ASCL1 drives SCLC disease progression and cell survival by regulating the expression of several proto-oncogenes including MYCL1, RET, SOX2, NFIB, and BCL2 [18, 19], as well as the DLL3 gene, which encodes an inhibitory ligand that suppresses Notch signaling in SCLC cells [20].