CXCR4 and breast carcinoma: 79,81 Similarly, pharmacologic inhibition of MIF reduced tumor cell growth and metastasis of osteosarcoma xenografts.83 Data exist showing that inhibition of CXCR4 signaling reduces intratumoral immunosuppression, resulting in increased efficacy of various immunotherapy regimens in murine models of breast cancer, pancreatic cancer, and melanoma.84 Although typically administered as a single subcutaneous injection, a phase I study examined the intratumoral effect of continuous infusion of plerixafor in patients with advanced pancreatic, ovarian, and colorectal cancers (NCT02179970).