CD44 and neoplasm: After sorting CD44-high and CD44-low populations from 7 days KPY organoids, we transplanted the same number of cells from each population by intratracheal instillation as described (Louie et al, 2022; Dost et al, 2020) (Fig. 5A), and the mice were euthanized two months after transplantation to quantify the tumor burden.