Previous studies have shown that CTLA-4 is a critical negative regulator of T cell-mediated immune responses through direct influence on Treg homeostasis [45] and that LAG-3 is linked to metastasis and prognosis of various cancers such as follicular lymphoma, lymphocytic leukaemia, lung cancer, and gastric cancer [46–49]. This evidence concerns the gene CTLA4 and lymphoid leukemia.