MYCN and neuroblastoma: Moreover, the expression of miR-558 or HIF-2α was higher in neuroblastic tumors with more aggressiveness (P=0.0011 and P=0.0255; Figure 7B), and in NB tissues with advanced INSS stage (P=0.0019 and P<0.0001; Figure 7B) or MYCN amplification (P=0.0455 and P=0.0244; Figure 7B).