Prognostic value of MYCN and ID2 overexpression in neuroblastoma

Background. The molecular mechanisms driven by overexpression of the MYCN gene in neuroblastoma are not well known. Whether MYCN overexpression in the absence of genomic amplification, or ID2 overexpression has prognostic value remains controversial. Procedure. Ninety-nine neuroblastic tumors from Memorial Sloan-Kettering Cancer Center and 12 neuroblastoma cell lines were analyzed by Affymetrix U95v2 Microarray System. The expression levels of the genes MYCN and 02 were determined by RT-PCR and immunohistochemistry and the clinical value of the overexpression of both genes was determined. Results. MYCN genomic amplification with overexpression was prognostic for survival (P = 0.0005). Stage 4 patients with MYCN amplification but without overexpression, had no increased likelihood of death, whereas cases with MYCN overexpression but no genomic amplification showed a low survival (P = 0.0096). ID2 did not correlate with MYCN expression (R = -0.23 for tumors and -0.27 for cell lines) or with survival (P = 0.8746). Conclusions. MYCN amplification was not related to clinical outcome in the absence of overexpression in neuroblastoma tumors. ID2 expression appears to be independent of MYCN expression and lacks prognostic value.