ASCL1 and small cell lung carcinoma: Previous research has indicated that the activated Notch signaling pathway suppresses the expression of hASH1 in SCLC cells, leading to cell cycle arrest and growth inhibition linked to the p21waf/cip1 and ras signaling pathway.502 Giachino et al. discovered that Notch signaling acts as a tumor suppressor in forebrain tumor subtypes.503 Their findings indicate that Notch signaling can collaborate with p53 to inhibit cell proliferation and tumor growth in grades II-III astrocytoma, proneural glioblastoma, and supratentorial primitive neuroectodermal tumor.