KRT19 and neoplasm: More importantly, and again in agreement with in vitro data, cleaved caspase-3 staining showed that the majority of KRT19+F4/80+ cells are apoptotic within Nupr1KO; KRASG12D; INK4A/ARFnull tumours, in stark contrast with their Nupr1WT counterparts, in which most apoptotic cells were found to be KRT19-F4/80+ macrophages (Fig 7B and C).