SPP1 and metastatic neoplasm: While the results indicated that recurrent metastatic tumors did not have significantly more macrophages than their primary breast tumor counterparts (Supplementary Fig. 10c), the percentage of OPN+ cells positively correlated with CD68+ macrophage infiltration significantly more in recurrent metastatic tumors than in primary breast tumors (p = 0.0390 vs p = 0.2713, respectively) (Supplementary Fig. 10d, e).