Exosomal miR-21 drives macrophage M2 polarization by targeting KLF3 and activating Nanog/Oct4 signaling in pancreatic neuroendocrine tumors [29,30,31,32], while breast cancer EVs transfer miR-10b to NK cells, downregulating MICB and impairing NK-mediated cytotoxicity; antagomir-mediated inhibition of miR-10b restores NK activation and eliminates metastases in vivo [33,34,35]. Here, MICB is linked to breast cancer.