To explore the mechanism promoting the accumulation of neutrophils at the metastatic site in response to chemotherapy after rebound, we next tested whether pancreatic cancer cells treated with chemotherapeutic drugs upregulate the expression of chemokines known to promote neutrophil migration, including CXCL1, 2, 5 and 8 (expressed in human only).38 We found that in human and mouse pancreatic cancer cells, the chemokines Cxcl1 and Cxcl2 are highly upregulated in response to gemcitabine treatment (figure 7A). This evidence concerns the gene CXCL1 and familial pancreatic carcinoma.