MPO and bone metastasis: CD15+MPO− TANs also correlated inversely with skin metastasis (P = 0.020), a trend was seen for association between CD15−MPO+ (MPO+) cells and lung metastasis (P = 0.059; Table 3), while CD15+MPO+ TANs showed a negative trend towards correlating with bone metastasis (P = 0.061).