CD4 and pancreatic neoplasm: Results from a heterotopic mouse model of PDAC using nonmetastatic murine Pan02 cancer cells and an orthotopic xenograft mouse model using metastatic human Panc-1 cancer cells revealed that pancreatic cancer expresses CCL5 to recruit CD4+Foxp3+ Treg cells, which have high levels of CCR5 [38, 39].