KRAS and neoplasm: Huang et al. (2015) generated pancreatic organoids carrying either a single KRAS-activating mutation or a p53R172H dominant-negative mutation. These organoids formed cystic structures with morphology similar to pancreatic intraepithelial neoplasia (PanIN) lesions both in vitro and in vivo. It is noteworthy that these PanIN organoids were not able to expand to form larger PanIN lesions or progress to the PDAC tumor stage upon in vivo transplantation into the mouse fat pad.