The possible mechanism is: DNAse I produced in the liver by AAV vectors reduced the presence of NETs in colon cancer metastases and enhanced local CD8 + T-cell infiltration [27]; orthotopic tumors using Kras-induced pancreatic cancer cells (KPC cells) engrafted in Pad4-deficient mice showed increased infiltration of activated CD8 + T cells and were more sensitive to PD-1 blocking mAbs [28]; and interleukin-17 has played a key role in the production of NETs via the induction of CXCR1/2 agonist chemokines, which attract neutrophils and elicit NETs. Here, PDCD1 is linked to malignant colon neoplasm.