KRAS and neoplasm: Studies with the KPC genetically engineered mouse model (GEMM) of PDAC, which expresses mutated Kras and p53 alleles in the pancreas due to Pdx1-driven Cre recombination [16], have suggested that pancreatic tumor masses have a paucity of blood flow [17–19] that can be enhanced to facilitate drug delivery to the tumor mass using therapies that promote tumor angiogenesis [19], or by targeting the stroma [17, 18].