MPO and colorectal carcinoma: However, a significantly higher (P<0.001) infiltration by MPO+ and CD15+ cells was detectable in CRC samples (mean: 26.7, median: 23, range 0–150 cells/punch for MPO (n = 1225) and mean: 16.4, median: 7, range 0–125 cells/punch for CD15 (n = 1191), respectively; figure 1E–F).