TAMs and MM have unique cell-cell interactions . (A) Upregulated MP ligand-MM receptor pairs clustered by interaction scores. (B) GO-term analysis of the 3 clusters of ligand-receptor pairs in panel A. (C) Upregulated MM ligand-MP receptor pairs clustered by interaction scores. (D) GO-term analysis of the 3 clusters of ligand-receptor pairs in panel C. (E) Flow cytometric analysis of surface expression of CD324, CD71, and CD29 on MM cells (CD138^hiGFP^hi) vs PCs (CD138^hiB220^–GFP^–), and VCAM-1 expression on TAM-IC vs TAM-NIC cells using Mann-Whitney t tests (n = 3 mice) with similar results from a second experiment (not shown). *P < .05; **P < .01; ***P < .001; ****P < .0001. Error bars represent standard deviation.