CTLA4 and neoplasm: Furthermore, through CTLA-4, Treg cells capture co-stimulatory molecules on DC by the process of transendocytosis (43), while in vitro assays have shown that Tregs down-regulate CD80 and CD86 expression in DC in a CTLA-4 and lymphocyte function-associated antigen (LFA)-1 dependent manner, highly blocking or weakening the signaling between APCs and anti-tumor specific T cells (44).