DNA copy number alterations in central primitive neuroectodermal tumors and tumors of the pineal region: an international individual patient data meta-analysis.

ABSTRACT

Little is known about frequency, association with clinical characteristics, and prognostic impact of DNA copy number alterations (CNA) on survival in central primitive neuroectodermal tumors (CNS-PNET) and tumors of the pineal region. Searches of MEDLINE, Pubmed, and EMBASE--after the original description of comparative genomic hybridization in 1992 and July 2010--identified 15 case series of patients with CNS-PNET and tumors of the pineal region whose tumors were investigated for genome-wide CNA. One additional case study was identified from contact with experts. Individual patient data were extracted from publications or obtained from investigators, and CNAs were converted to a digitized format suitable for data mining and subgroup identification. Summary profiles for genomic imbalances were generated from case-specific data. Overall survival (OS) was estimated using the Kaplan-Meier method, and by univariable and multivariable Cox regression models. In their overall CNA profiles, low grade tumors of the pineal region clearly diverged from CNS-PNET and pineoblastoma. At a median follow-up of 89 months, 7-year OS rates of CNS-PNET, pineoblastoma, and low grade tumors of the pineal region were 22.9 ± 6, 0 ± 0, and 87.5 ± 12 %, respectively. Multivariable analysis revealed that histology (CNS-PNET), age (≤2.5 years), and possibly recurrent CNAs were associated with unfavorable OS. DNA copy number profiling suggests a close relationship between CNS-PNET and pineoblastoma. Low grade tumors of the pineal region differed from CNS-PNET and pineoblastoma. Due to their high biological and clinical variability, a coordinated prospective validation in future studies is necessary to establish robust risk factors.