- Activated by CCL2, CXCL1, and CXCL5 and VEGF released by cancer cells- Tumors can paralyze DCs through the induction of PD-1 expression- CTLA-4 is able to competently bind to CD80 and CD86 on DCs, preventing the activation of CD8+ T cells by DCs. This evidence concerns the gene CTLA4 and cancer.