TAL1 and acute lymphoblastic leukemia: T-ALL cases harboring NOTCH1 mutations and STIL-TAL1 positive cases had lower CD44 expression than wild type cases (NOTCH1 mutated MFI 39.4 [5.8–866.3], STIL-TAL1 positive MFI 19.3 [3.9–234.7], NOTCH1 mutated and STIL-TAL1 positive MFI 20.9 [6.7–84.7], STIL-TAL1 negative and NOTCH1 WT MFI 68.75 [3.3–272.3], p = 0.017, p = 0.031 and p = 0.034; Figure 5.