CCL2 and melanoma: CCL2 overexpression in primary murine melanoma led to monocyte infiltration,63 and CCL2 blockade in a human melanoma xenograft model led to a reduction in macrophage infiltration.64 Although CD8+ T-cells also express the receptors for CCL2, post-translational modification of CCL2 such as nitration by reactive nitrogen species in the tumour is found to inhibit CD8+ T-cell recruitment via this axis.65