Recently, MDSCs have also been implicated in tumor refractoriness to anti-VEGF treatment.(22) Bv8 (prokineticin 2), expressed in the bone marrow, modulates mobilization of CD11b+Gr-1+ cells from the bone marrow during tumor development and also promotes angiogenesis locally.(23) These studies suggest that tumor-infiltrating bone marrow–derived MDSCs change the dynamics in the primary tumor microenvironment and result in alterations in the signaling cascade in tumor cells, promoting tumor cell invasion and metastasis. Here, PROK2 is linked to neoplasm.