CCL2 and neoplasm: Tumors mostly produce a minute number of chemokines, resulting in inefficient targeting of effectors to tumors.155 Despite their intrinsic enhancement of T-cell infiltration, OVs have been genetically engineered to express chemokines such as CCL2,214 CCL5,148 CCL19,311 CXCL11154 or CXCL9312 to recruit DCs, memory T lymphocytes, CD8+ cytotoxic T cells, and CD4+ T helper cells into the tumor core, resulting in the expansion of antitumor activity.