A denser presence of macrophages along with tumor regression has shown to precede the infiltration of CD8+ T cells.150 Numerous approaches choose synthetic peptides, recombinant proteins, whole tumor cells, viral vectors, bacteria or nucleic acids as vaccination candidates to activate T cells via antigen-presenting cells, which are mostly dendritic cells.151 Among these, some regimens that used GM-CSF as an adjuvant generated obvious immune responses.151,152 Sipuleucel-T was the first therapeutic vaccine approved by the FDA to be used in a particular group of prostate cancer patients. Here, CSF2 is linked to neoplasm.