F2R and cancer: Treatment with the CM of control siRNA–transfected RAW 264.7 cells significantly increased CXCL1 levels in the B16F10 and LLC cancer cell lines; this enhancement was suppressed in cancer cells treated with the CM of PAR1 siRNA–transfected RAW 264.7 cells but not in those treated with the CM of control siRNA or PAR2 siRNAs-transfected RAW 264.7 cells (Figure 6C).