ABSTRACT
Choroid plexus tumors are rare neoplasms that mainly affect children. They include papillomas, atypical papillomas, and carcinomas. Detailed genetic studies are rare, and information about their molecular pathogenesis is limited. Molecular inversion probe analysis is a hybridization-based method that represents a reliable tool for the analysis of highly fragmented formalin-fixed paraffin-embedded tissue-derived DNA. Here, analysis of 62 cases showed frequent hyperdiploidy in papillomas and atypical papillomas that appeared very similar in their cytogenetic profiles. In contrast, carcinomas showed mainly losses of chromosomes. Besides recurrent focal chromosomal gains common to all choroid plexus tumors, including chromosome 14q21-q22 (harboring OTX2), chromosome 7q22 (LAMB1), and chromosome 9q21.12 (TRPM3), Genomic Identification of Significant Targets in Cancer analysis uncovered focal alterations specific for papillomas and atypical papillomas (e.g. 7p21.3 [ARL4A]) and for carcinomas (16p13.3 [RBFOX1] and 6p21 [POLH, GTPBP2, RSPH9, and VEGFA]). Additional RNA expression profiling and gene set enrichment analysis revealed greater expression of cell cycle-related genes in atypical papillomas in comparison with that in papillomas. These findings suggest that atypical papillomas represent an immature variant of papillomas characterized by increased proliferative activity, whereas carcinomas seem to represent a genetically distinct tumor group.
Subject(s)
Carcinoma/genetics , Choroid Plexus Neoplasms/genetics , Chromosome Aberrations , Genomics , Papilloma, Choroid Plexus/genetics , Adolescent , Adult , Child , Child, Preschool , Chromosomes, Human , Female , Follow-Up Studies , Humans , Infant , Infant, Newborn , Kaplan-Meier Estimate , Male , Middle Aged , Otx Transcription Factors/genetics , TRPM Cation Channels/genetics , Transcriptome , Young AdultABSTRACT
BACKGROUND: Choroid plexus carcinomas (CPC) are rare brain tumors with a dismal prognosis. Although the role of surgery has been well established, the question of whether chemotherapy improves the prognosis is still under discussion. METHODS: We created a database of all cases of choroid plexus tumors (CPT) reported in the literature up to the year 2004 to determine prognostic factors and different therapeutic modalities. This database was validated by comparison with an existing database of cases until 1997. RESULTS: Of 857 documented cases of CPT (median patient age at diagnosis, 3 years), 347 were CPC, 15 atypical choroid plexus papilloma (APP), and 495 choroid plexus papilloma (CPP). Histology was a significant prognostic factor (P < .0001; log rank). Within the subgroup of patients with CPC, both surgery and irradiation were linked to a better prognosis (P < .005). The 104 CPC patients who received chemotherapy had a statistically better survival than those without chemotherapy (P = .0004). When subgroups were defined by radiation treatment, chemotherapy remained beneficial in the subgroup of nonirradiated tumors (P = .0001). The benefit of chemotherapy was also significant when the analysis was restricted to the subgroup of patients with less than completely resected CPC (2-year overall survival (OS) 54.8 +/- 7% (standard deviation (SD) vs. 24.4 +/- 7%, P < .0001) and when this subgroup was further divided into smaller subgroups. Likewise, in a multivariate analysis, chemotherapy was highly significantly linked to better prognosis (P = .0001). CONCLUSION: Patients with less than completely resected CPC should receive chemotherapy.
