A patient with medulloblastoma in its early developmental stage

Abstract

<jats:p>Medulloblastoma is the most frequent malignant brain tumor of the posterior fossa in children and is considered an embryonal tumor. It has been suggested that medulloblastomas be categorized into 4 distinct molecular subgroups— WNT (DKK1), SHH (SFRP1), Group 3 (NPR3), or Group 4 (KCNA1)—since each subgroup is distinct and there is no overlap. The authors report on a 13-year-old boy with medulloblastoma. He presented with sudden-onset nausea and vomiting due to intratumoral hemorrhage. The medulloblastoma was thought to be in an early developmental stage because the tumor volume was extremely small. Immunohistochemical analysis showed that the tumor was mainly composed of DKK1- and NPR3-positive areas. The individual areas of the tumor stained only for DKK1 or NPR3, with no overlap—that is, DKK1 and NPR3 expression were mutually exclusive. Samples obtained by laser microdissection of individual areas and subjected to mass spectrometry confirmed that the expression patterns of proteins were different. Fluorescence in situ hybridization for chromosome 6 showed there were 2 distinct types of cells that exhibited monosomy or disomy of chromosome 6. These results demonstrated that distinct subtypes of medulloblastoma may be present within a single tumor, an observation that has not been previously reported. Our findings in this case indicate that early-stage medulloblastoma may include more than 1 distinct subtype and hint at factors involved in the origin and development of medulloblastomas.</jats:p>

Imaging Biomarkers for Adult Medulloblastomas: Genetic Entities May Be Identified by Their MR Imaging Radiophenotype

“…However, hemorrhage was also reported in WNT-activated medulloblastomas. 27,33 Therefore, this MR imaging biomarker should be re-evaluated in a larger independent cohort.…”

Meningioma in Down Syndrome

“…The gene and molecular analysis in this study was conducted under our protocol (#231) approved by the Research Ethics Committee of the Institutional Review Board of Kumamoto University Hospital as previously reported (22).…”

“…Fluorescence in situ hybridization (FISH) was performed by use of formalin-fixed, paraffin-embedded tissue samples and the following probes in the Cytogenic Testing Group, Molecular Genetic Testing Department, Clinical Testing Center, Mitsubishi Chemical Medicine Corporation, Tokyo, Japan (22). TUPLE1 [22q11.2] SpectrumOrange (Abbott Laboratories, Abbott Park, Illinois, USA) and ARSA [22q13.3] SpectrumGreen probes (Abbott Laboratories) were used to detect q12 on chromosome 22 where the neurofibromin 2 (NF2) gene resides, and Vysis LSI 21 SpectrumOrange probes (Abbott Laboratories) were used for the centromere 21q22.13-q22.2 region.…”

Letter to the Editor: Temporal evolution of medulloblastoma subgroups

“…7 The presence of distinct WNT and Group 3 cells in a single tumor mass supports a framework that recognizes intratumoral heterogeneity as a natural component in the spatial and temporal evolution of medulloblastoma. The cancer stem cell hypothesis accounts for intratumoral heterogeneity by having a developmentally primitive cell at the apex of the hierarchy with a spectrum of more differentiated cells as one goes down this hierarchy.…”