Studying Biomarkers in Samples From Patients With High-Risk Neuroblastoma

DISEASE CHARACTERISTICS: * Snap-frozen neuroblastoma (NB) tumors collected at diagnosis (Objectives 1 to 3) * High-risk stage 3 or 4 NB AND MYCN non-amplified, i.e., exclude stage 4 infants who are not high-risk * Up to five high-risk (\> 18 months, unfavorable histology) stage 3/MYCN non-amplified tumors * Patients preferably treated on protocol COG-A3973 or similar protocols with myeloablative therapy * At least 3 years of follow-up for those with no event (current evidence suggests that ALT+ NBs often relapse late, i.e., 2 years or longer from diagnosis) * NB tumor DNA collected at diagnosis (Objectives 2 \& 3) * High-risk stage 3 or 4 NB as for Objective 1, except for MYCN status * Stage 4 tumors are preferred; may include up to seven high-risk stage 3 tumors with similar distribution of MYCN-amplified and non-amplified tumors * Frozen serum from NB patients (Objective 5; 2nd stage of project) * Paired serum obtained at diagnosis from patients with ALT+ or ALT- tumors identified in Objective 2 PATIENT CHARACTERISTICS: * Not specified PRIOR CONCURRENT THERAPY: * See Disease Characteristics