Ependymomas: Prognosis based on genetic aberrations

Ependymoma are primary tumors of the central nervous system (CNS) that typically arise from the wall of the cerebral ventricles or from the spinal canal. The pathogenesis of these tumors is poorly understood, and prognostic assessment based only on histologic features and clinical parameters is still difficult. Although numerous genetic abnormalities have been described, a reliable molecular prognostic marker is still not available due to the heterogeneity of this tumor group. In a microsatellite analysis we found frequent deletions in chromosomes 6, (particularly in the regions 6q15-q16, 6q21-q22.1, and 6q24.3-q25.3), in chromosome 9, (especially in 9p21 and 9q34) and in chromosome 22q (in the segment 22q11.21-q12.2 and 22q13.3). The highest number of aberrations on chromosome 6 we found in a short segment of 6q25.3 containing the SNX9 and SYNJ2 genes and we could demonstrate a relation to a significant longer overall survival in paediatric patients. For chromosome 9 highly deleted was the region 9q31.3-33.2 containing the DCRI gene, which may play a role in the prognostic evaluation for ependymomas in adults. The chromosome 22 showed two ‘hot spots’: 22q11.21-q12.2 and 22q13.1-1-22q13.3. There was a significant association between aberrations and WHO grade of the tumor: grade II ependymomas showed significantly more aberrations than anaplastic ependymomas WHO grade III. The aim of these studies was to define characteristics genomic imbalances and to correlate them with clinical data in an attempt to describe aberrations with prognostic value in homogenously treated ependymoma patients.