MAPK3 and frontotemporal dementia: We investigated whether drug treatment schedules might influence apoptosis and the expression of phosphorylated extracellular signal-related kinase 1/2 (p-ERK1/2), ERK1/2, and thymidylate synthase (TS); the former and latter are major determinants of the sensitivity of cells to regorafenib and FTD, respectively.