CX3CL1 and neoplasm: Recent studies report that TGF-β participates in additional immune-obstructive mechanisms, constructing stromal barriers that exclude lymphocytes from the tumor parenchyma, disrupting NK cell tumor-trafficking by negatively modulating the CX3CL1/CX3CR1 chemokine/chemokine receptor axis, curbing NK cell cytotoxicity in metastatic breast cancer by restricting NK cell metabolism and regulating leukemia cell susceptibility against NK cell targeting by down regulating expression of CD48 (147–151).