Loco-regional tumors (stage 1, 2, and 3) displayed more heterogeneous expression patterns (Figure 2B and 2C; Additional file 1), with staining values being highest in differentiating NB, where intense nuclear staining was observed in >75% of neuroblastic cells (13/32) (Figure 2B; Additional file 1), and lowest in stage 3 MYCN amplified NB composed mainly of undifferentiated neuroblasts with undetectable immunoreactivity, similar to stage 4 NB cases (Figure 2C, Table 1, Additional file 1). The gene discussed is MYCN; the disease is neuroblastoma.