CXCR2 and colorectal carcinoma: Similarly, the addition of an antagonist of CXCR2 (SB225002), the cognate receptor of CXCL1 (ref. 19), abrogated the induction of MDSC migration in conditioned medium from all three CRC cell lines pre-incubated with P. anaerobius (P < 0.01; Extended Data Fig. 4e).