MYCN and myeloid sarcoma: Finally, to dissect the relative contribution of the two gene signatures as compared to the other variables known to associate with patient survival in univariate analysis (namely, INRG L1, L2, and MS, absence of MYCN amplification, age <18 months, high T-cell infiltration and high expression of THBD and NCR1 gene signatures), a multivariate Cox regression analysis was performed.