To explore the possibility that such mechanisms exist, we examined the effects of MIBG and metformin as single agents and in combination on the expression of genes encoding biomarkers of favorable outcome in NB (EFNB2, EFNB3, EPHB6, NTRK1, CD44 and MIZ-1) in NB cells. The gene discussed is NTRK1; the disease is neuroblastoma.