Low NDRG1 mRNA expression predicts a poor prognosis in neuroblastoma patients

Purpose: N-myc downstream regulated gene 1 (NDRG1) markedly reduces metastasis of numerous tumors. However, NDRG1's function in malignant tumors has not been fully determined. Therefore, we investigated the association of NDRG1 expression with clinical outcomes in neuroblastoma (NB) patients. Methods: We obtained total RNA from residual cancer cells using microdissection from NB patients. Furthermore, we examined the expression of NDRG1 in NB patients using immunohistochemical staining. Results: Of the 48 patients observed, low NDRG1 expression was associated with poor prognostic factors such as primary tumor size and MYCN amplification. Low expression of NDRG1 was associated with a poor prognosis (p = 0.001) and multivariate analysis identified low expression of NDRG1 as an independent risk factor for predicting poor prognosis in NB patients. Furthermore, in the MYCN non-amplification group (n = 33), low expression of NDRG1 was associated with a poor prognosis (p = 0.001). Immunohistochemical analysis showed NDRG1 expression at the plasma membranes of NB cells. NDRG1 expression levels were also correlated with expression of NDRG1 mRNA. Conclusion: We confirmed that low NDRG1 expression is a significant and independent prognostic indicator in NB by multivariate analysis. Furthermore, NDRG1 may be a novel prognostic marker in MYCN non-amplification NB patients.