TP53 and pancreatic neoplasm: The discovery that our generated ATM-deficient pancreatic tumor cells expressed p53 but not p16Ink4A/p19Arf concurs with the observation that KrasG12D-induced murine pancreatic tumors have frequent loss of p16Ink4A and p19Arf or loss of p53, but not simultaneous loss of the 3 tumor suppressors21.