ASCL1 and neoplasm: Recent profiling studies involving both primary human and mouse tumours supported various models of distinct SCLC molecular subtypes defined by relative expression of key transcription regulators including ASCL1) (achaete-scute homolog 1), NeuroD1 (neurogenic differentiation factor 1), YAP1 (yes-associated protein 1), and POU2F3 (POU domain class 2 homeobox 3) [13].