Upon tumor antigen-recognition, recirculating memory T cells can develop highly efficient secondary responses, resulting in tumor cell killing, cytokine release, etc. In a study on mouse melanoma, it has been shown that CD8 mAb treatment inducing 82%–99% reduction of circulating CD8 T cells resulted in rapid metastasis outgrowth in visceral organs, suggesting that CD8 T cells were cytostatic and kept in check disseminated dormant tumor cells in this model (86). This evidence concerns the gene CD8A and melanoma.