CCR1 and neoplasm: This autocrine production of CCL3 and CCL4 by HSC, confirmed at the protein level by cytokine beads array and intracellular staining, explained the conundrum that MDSCs can be differentiated in the absence of CCR1 and CCR5 ligands using recombinant cytokines such GM-CSF and IL6 or tumor conditioned media deficient of CCL3 and CCL4.