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  • 1
    Abstract: Molecular subclassification is rapidly informing the clinical management of medulloblastoma. However, the disease remains associated with poor outcomes and therapy-associated late effects, and the majority of patients are not characterized by a validated prognostic biomarker. Here, we investigated the potential of epigenetic DNA methylation for disease subclassification, particularly in formalin-fixed biopsies, and to identify biomarkers for improved therapeutic individualization. Tumor DNA methylation profiles were assessed, alongside molecular and clinical disease features, in 230 patients primarily from the SIOP-UKCCSG PNET3 clinical trial. We demonstrate by cross-validation in frozen training and formalin-fixed test sets that medulloblastoma comprises four robust DNA methylation subgroups (termed WNT, SHH, G3 and G4), highly related to their transcriptomic counterparts, and which display distinct molecular, clinical and pathological disease characteristics. WNT patients displayed an expected favorable prognosis, while outcomes for SHH, G3 and G4 were equivalent in our cohort. MXI1 and IL8 methylation were identified as novel independent high-risk biomarkers in cross-validated survival models of non-WNT patients, and were validated using non-array methods. Incorporation of MXI1 and IL8 into current survival models significantly improved the assignment of disease risk; 46 % of patients could be classified as 'favorable risk' (〉90 % survival) compared to 13 % using current models, while the high-risk group was reduced from 30 to 16 %. DNA methylation profiling enables the robust subclassification of four disease subgroups in frozen and routinely collected/archival formalin-fixed biopsy material, and the incorporation of DNA methylation biomarkers can significantly improve disease-risk stratification. These findings have important implications for future risk-adapted clinical disease management.
    Type of Publication: Journal article published
    PubMed ID: 23291781
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  • 2
    ISSN: 1433-0350
    Keywords: Key words Children ; Medulloblastoma/PNET ; Chemotherapy ; Risk factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the risk factors for recurrence of MB/PNET we analyzed the medical records of 157 patients treated at the Children's Memorial Health Institute between February 1981 and February 1997. The following factors were evaluated: age at diagnosis, gender, tumor size, tumor cells in the CSF, postoperative status, extent of resection and methods of treatment. We evaluated chemotherapy (CHT) doses, interval between courses, interval between surgery (S) and first course of CHT, interval between S and radiotherapy (RTX), and breaks during RTX. We divided patients into six groups: S alone, S+CHT, S+RTX, S+CHT+ RTX, S+RTX+CHT, S+CHT+RTX+ CHT. Age at diagnosis, gender, tumor size, extent of resection, postoperative status, intervals between courses of CHT, between S and the first course of CHT, and between S and RTX, and breaks during RTX had no statistical influence on relapse occurrence. Tumor cells in CSF were routinely checked for from January 1992 onward. In this group of 75 patients, 40 had tumor cells positive at surgery (28 relapsed), while in the group of 35 patients with negative tumor cells 14 relapsed (P=0.004). Out of 26 patients treated with S+RTX alone, 13 relapsed. Among 14 patients treated with S+RTX and prolonged CHT 6 relapsed. Out of 14 patients treated with S+CHT 13 relapsed; among 49 who received S+CHT+RTX 35 relapsed; and out of 51 patients treated with S+CHT+RTX+CHT 30 relapsed. In the multivariate analysis of treatment methods chemotherapy implemented after radiotherapy had a positive, though not statistically significant, influence on outcome (P=0.06). Among those receiving CHT the mean percentage of the ideal dose administered had a statistically significant influence on relapse: in the group of relapsed patients the mean dose was 76.1%, while in the group in continuous remission it was 83.7% (P=0.0013). On the basis of our data, we conclude that the presence of tumor cells in the CSF had a significant influence on the occurrence of relapse. Administration of appropriate doses of chemotherapy is extremely important for the occurrence of relapse and the final outcome of treatment. Prolonged adjuvant chemotherapy after radiotherapy seems to lower the risk of recurrence.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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