KRAS and neoplasm: Indeed, preclinical evidence indicated that a “sensitizer” background (specifically oncogenic Kras activation) is a necessary prerequisite when trying to identify factors (genetic or non-genetic) that accelerate progression of pancreatic cancer in mouse models (Perez-Mancera et al., 2012) where genes’ inactivation due to sleeping beauty transpositions was not sufficient to drive tumor formation in the absence of Kras activation.