Following PEGPH20 treatment in aggressive murine models of PDAC, we have found that administration of ST transformed with an shRNA plasmid specific to the immunosuppressive protein indoleamine 2,3-dioxygenase [13,14], results in enhanced ST colonization and intratumoral recruitment of PMN which are involved in the direct killing of surrounding tumor cells. This evidence concerns the gene IDO2 and neoplasm.