For instance, pre-treatment of monocyte-derived dendritic cells with the tumour conditioned media containing high levels of the chemokines CCL2, CXCL1, CXCL5 and VEGF inhibited the upregulation of CD86, CD83, CD54 and HLA-DR, enhancing IL-10 and reducing IL-12 secretion, and causing progressive increased expression of PD-1 on cancer-infiltrating DCs followed by paralysis of DCs [86]. Here, PDCD1 is linked to cancer.