Exploring IDH1 and IDH2 Mutations in Paediatric Medulloblastoma.

Abstract

Medulloblastoma (MB) in children is associated with distinct molecular subgroups, reflecting substantial biological heterogeneity. The presence of isocitrate dehydrogenase 1 (IDH1) and IDH2 mutations in paediatric MB has been rarely reported and not routinely investigated. Our study included 23 samples from paediatric patients diagnosed with MB. Hotspot alterations at codons IDH1 R132 and IDH2 R172 were examined using Sanger sequencing following polymerase chain reaction (PCR). The mean age of the patients was 10 years (SD: 4.25), comprising 17 males and 6 females. All cases exhibited classical histological features of MB. β-Catenin expression was observed in four cases (17.4 %), while 19 cases (82.6 %) showed no expression. No statistically significant differences in progression-free survival (PFS) were found between MBs with positive or negative β-catenin expression (P = 0.6). Radiotherapy alone was administered to four patients (17.4 %), while 19 patients (82.6 %) received combined radiotherapy and chemotherapy. The median PFS was 383 days (1 year and 18 days). IDH1 R132 or IDH2 R172 hotspot mutations were not detected in any of the samples. The absence of IDH1 or IDH2 mutations in paediatric MB may be attributed to differences in mutational profiles and cellular origins in childhood MB, despite its histomolecular similarities with adult MB.