In vitro, co-culture of monocyte-derived human dendritic cells activated with lipopolysaccharide and CTLA-4+ breast cancer cell line, resulted in decreased expression of MHC class II, and costimulatory cell surface molecules (CD40, CD80, CD83, CD86) on dendritic cells and inability to activate T cells [133]. Here, CTLA4 is linked to breast carcinoma.