Immune cells found within the TME are often “tumor-associated” and promote tumor growth by playing an immunosuppressive function; immune cells within the TME include tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), regulatory T cells (Treg cells), versus immune cytotoxic CD8+ T cells, CD4+ T cells, and natural killer cells (NK cells) (Whiteside 2008; Hanahan and Weinberg 2011). Here, CD4 is linked to neoplasm.