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Intracranial Orthotopic Allografting of Medulloblastoma Cells in Immunocompromised Mice
Published on: October 3, 2010
MRI surrogates for molecular subgroups of medulloblastoma
S Perreault1, V Ramaswamy2, A S Achrol3
1From the Department of Neurology (S. Perreault, S.S., P.G.F., S. Partap, Y.J.C.), Division of Child NeurologyDivision of Child Neurology (S. Perreault), Centre Hospitalier Universitaire Sainte-Justine, Montreal, Quebec, Canada.
Background And Purpose:
Recently identified molecular subgroups of medulloblastoma have shown potential for improved risk stratification. We hypothesized that distinct MR imaging features can predict these subgroups.
Materials And Methods:
All patients with a diagnosis of medulloblastoma at one institution, with both pretherapy MR imaging and surgical tissue, served as the discovery cohort (n = 47). MR imaging features were assessed by 3 blinded neuroradiologists. NanoString-based assay of tumor tissues was conducted to classify the tumors into the 4 established molecular subgroups (wingless, sonic hedgehog, group 3, and group 4). A second pediatric medulloblastoma cohort (n = 52) from an independent institution was used for validation of the MR imaging features predictive of the molecular subtypes.
Results:
Logistic regression analysis within the discovery cohort revealed tumor location (P < .001) and enhancement pattern (P = .001) to be significant predictors of medulloblastoma subgroups. Stereospecific computational analyses confirmed that group 3 and 4 tumors predominated within the midline fourth ventricle (100%, P = .007), wingless tumors were localized to the cerebellar peduncle/cerebellopontine angle cistern with a positive predictive value of 100% (95% CI, 30%-100%), and sonic hedgehog tumors arose in the cerebellar hemispheres with a positive predictive value of 100% (95% CI, 59%-100%). Midline group 4 tumors presented with minimal/no enhancement with a positive predictive value of 91% (95% CI, 59%-98%). When we used the MR imaging feature-based regression model, 66% of medulloblastomas were correctly predicted in the discovery cohort, and 65%, in the validation cohort.
Conclusions:
Tumor location and enhancement pattern were predictive of molecular subgroups of pediatric medulloblastoma and may potentially serve as a surrogate for genomic testing.
Insights
Distinct MR imaging features can predict medulloblastoma molecular subgroups, potentially replacing genomic testing for risk stratification. Tumor location and enhancement patterns accurately identified subgroups in pediatric patients.
Area of Science:
- Neuro-oncology
- Radiology
- Genomics
Background:
- Medulloblastoma molecular subgroups offer improved risk stratification.
- Identifying these subgroups non-invasively is crucial for treatment planning.
Purpose of the Study:
- To determine if distinct MR imaging features can predict medulloblastoma molecular subgroups.
- To validate MR imaging features as potential surrogates for genomic testing.
Main Methods:
- Retrospective analysis of pretherapy MR imaging and tumor tissue from two pediatric cohorts (n=47 and n=52).
- MR imaging features assessed by blinded neuroradiologists.
- Tumor tissues classified into molecular subgroups (wingless, sonic hedgehog, group 3, group 4) using NanoString assay.
Main Results:
- Tumor location and enhancement pattern significantly predicted medulloblastoma subgroups.
- Specific locations and enhancement patterns were highly predictive of wingless, sonic hedgehog, group 3, and group 4 tumors.
- The MR imaging-based model correctly predicted 66% of subgroups in the discovery cohort and 65% in the validation cohort.
Conclusions:
- MR imaging features, specifically tumor location and enhancement patterns, are predictive of medulloblastoma molecular subgroups.
- These imaging findings may serve as a non-invasive surrogate for genomic subtyping in pediatric medulloblastoma.
