MPO and breast carcinoma: To investigate the potential effect of TANs and MPO-expressing cells (CD15+MPO+ and CD15−MPO+) on breast tumor progression, we initially performed bivariate Spearman ́s 2-tailed correlation analyses test in relation to clinicopathological features in the primary tumors (PT; NHG, tumor size, nodal stage, breast cancer subtype, Ki67) and age at PT or metastasis (Table 1).