We detected CK + SYP + cells in serial-passaged PDX tumor tissue (up to at least 6 passages, passage 2 shown-Fig. 2c) that co-stained with the human Ku80 protein (Supplementary Fig. 1b), indicating that these dual positive cells in human PDA are tumor cell-derived, since normal islets would not be expected to survive the time it takes for PDXs to establish nor propagate in serial passage. This evidence concerns the gene SYP and Patent ductus arteriosus.