MYCN and acute lymphoblastic leukemia: MYCN expression in T-ALL samples was significantly higher than that in bone marrow from healthy individuals (mean expression ± 95% CI: 5.57 ± 0.25, T-ALL; 4.44 ± 0.08, healthy donor BM; P< 0.0001, Student t test, two-tailed) and 40% of T-ALL samples expressed MYCN at a level higher than the mean + 3SD of expression in normal bone marrow (Fig. 1A).