MMP9 and neuroblastoma: Since over-expression of NDRG2 suppressed the expression of VEGF and MMP-9 in NB cells (Additional file 2: Figure S2A), and knockdown of NDRG2 rescued ITLN1-induced down-regulation of VEGF and MMP-9 (Additional file 2: Figure S2B), we believed that ITLN1 regulated the expression of VEGF and MMP-9 through modulating NDRG2.