Here, the role of CD4+ T cells may be through support for CD8+ T cell activation as an early source of IL-2 [36], cooperation with CD8+ T cells during the effector phase to kill tumour stroma more effectively [37], and/or as an important source of IFN-γ production within the tumour microenvironment (Figure 2D and [38]). Here, CD4 is linked to neoplasm.