PF4 and prostate cancer: Since there is no increase of cAMP amount after CXCL4/PF4 or CXCL10/IP10 treatment in the prostate cancer cell lines, m-calpain activities remained at same levels compared to the untreated cells (Figure 5E), suggesting that inhibition of cell migration via the CXCR3B pathway was not active in prostate cancer cells.