MYCN and neuroblastoma: In 42 primary NB cases (Additional file 1: Table S4), higher HNF4A-AS1 levels were observed in tumor tissues and serum of patients with poor differentiation (P = 0.0013 and P = 0.0097), advanced INSS stages (P = 0.0051 and P = 0.0016), or MYCN amplification (P < 0.0001 and P = 0.0009, Additional file 1: Figure S4b).