Likewise, activated CD4+ and CD8+ T cells as assessed by CD69 positivity were more abundant in mice that received St6galnac4−/− T-ALL cells as compared to mice that received WT T-ALL (CD69+ CD4+: 0.4% vs. 0.2% of CD4+ T cells; CD69+ CD8+: 1.8% vs. 1.5 % of CD8+ T cells) (Fig. 3D). This evidence concerns the gene CD69 and acute lymphoblastic leukemia.