CCR1 and neoplasm: To overcome these difficulties, we used the 4PD nanoplatform that targets tumor-infiltrating myeloid cells to determine the relative contributions of CCR1, 2, 5, and 7 silencing on myeloid cell function in tumor hosts.20 Our study provides evidences for a synergistic and redundant role of CCR1 and 5 in mediating cancer-induced myelopoiesis and myeloid cell protumoral polarization.