This distinctive “blast gate” (CD45bright) (Figure 2A) was reproducibly seen for T-ALL in all analyzed mice (n = 74) from different experiments addressing the role of several genes in the leukemogenesis, for example, ΔTRKA [15], TRKA/NGF [13], TRKB/BDNF [12], and p53 (in p53 knock-out and p53/FLT3 double transgenic mice). This evidence concerns the gene NTRK2 and acute lymphoblastic leukemia.