CD4 and breast cancer: This BC-derived GM-CSF seems to play a pro-tumorigenic role and as an endogenous signal, develops an immunosuppressive microenvironment by inducing plasmacytoid DCs (pDCs)’s activation, which in turn deviates naive CD4+ T-cells and macrophages into a regulatory Th2 response and pro-invasive TAM-like phenotype, respectively [128], inducing an EMT/stemness-like invasive phenotype [129] or accumulating Arginase 1 expressing myeloid cells [127].