The downstream chemokines of IL-17B–IL-17RB signaling promote MQ and endothelial cell recruitment for enhancement of cancer cell survival and metastasis. (A and B) Soft agar colony formation assay (A) and invasion assay (B) using CFPAC-1 cells infected with shLacZ, shCCL20, shCXCL1, shIL8, shTFF1, and shIL-17RB. (C and D) Quantification of cancer cells, F4/80-expressing MQs (C) and TUNEL (D) staining in lung of mice 8 and 24 h, respectively, after intravenously injected with parental, or IL-17RB–depleted, GFP/LUC-tagged CFPAC-1 cells from immunofluorescence assays. (E) Quantification of CD31⁺ cells in tumors derived from mice 2 wk after being orthotopically injected with parental, IL-17RB, CCL20, CXCL1, IL-8, or TFF1-depleted GFP-LUC-tagged CFPAC-1 cells from IHC assays. (F) IHC of IL-17RB (brown) and CD31 (red; used as a marker for microvessel invasion [MVI]) in human pancreatic cancer. Boxes show the enlarged areas. (G) Correlation between IL-17RB expression and MVI in 111 pancreatic cancer cases. Data were derived from IHC analysis (F) and the means ± SD are shown. χ² test was used.