Taken together, these pieces of evidence show that casticin effectively inhibits stemness in CCSLCs by suppressing DNMT1 activation and expression, and as such, it is a promising epigenetic drug candidate to target not only cancer cells but also cancer stem-like cells, which are the most difficult cancer sub-population being characterized by recurrence, metastasis, heterogeneity, multidrug resistance, and radiation resistance (Yang et al., 2020). Here, DNMT1 is linked to cancer.