Enhanced recruitment of Smad3-KO-BMDN over that of Smad3-WT-BMDN into the TME was demonstrated in an adoptive transfer experiment in which equal numbers of dye-labeled Smad3-WT and Smad3-KO-BMDN were injected into tumor-bearing mice, and the TME examined 24 h later (Supplementary Fig. 10). Here, SMAD3 is linked to neoplasm.