A, Expression of granular effector molecules by neutrophils. B, Mean expression value of haptoglobin (Hp) across neutrophils and tumor-associated myeloid cells. C, Serum HP levels in mice with small (S), medium (M), large (L) tumors and naive mice. D, Correlation between the frequency of Gr1hi cells in blood and the serum HP concentration. E, HP levels in serum from healthy donors (n=4) and breast cancer patients (n=10). * P<0.05; ** P<0.01.