The variability in expression of ASCL1 in different cell lines (Wylie et al., 2015; Alleboina et al., 2021) points to the possibility that different tumours are trapped at various stages of a developmental trajectory in which ASCL1 is usually only transiently expressed, and so could result in ASCL1 playing a pro-proliferative or pro-differentiation function in different cellular contexts. Here, ASCL1 is linked to neoplasm.