CXCL12 and neoplasm: Interestingly, an oncolytic virus-based approach, consisting in cloning a murine Fc fragment of IgG2a that works as a CXCR4 antagonist into the genome of the oncolytic vaccinia virus, was tested in ovarian CSCs and reduced the CSC population via a reduction in CXCL12 levels in ascites, and reduced recruitment of ECs, MDSCs and plasmacytoid DCs to the tumor.