Molecular diagnostics in pediatric glial tumors
description
Transcript of Molecular diagnostics in pediatric glial tumors
Molecular diagnostics inpediatric glial tumors
Joon-Hyung Kim, MSIVWeill Cornell Medical College
Tumor type Molecular phenotype
Association
Oligodendroglioma
1p/19q codeletion Adults > Peds
Ganglioglioma BRAF V600E Peds > AdultsPXA BRAF V600E Peds = Adults
Mesenchymal histologyPilocytic astrocytoma
BRAF-KIAA1549 Tumor location/resectability (Cerebellar > Non-cerebellar)
DIPG 1q gain, 17p lossH3F3A, HIST1H3B mutations (K27M)
Peds > AdultsDIPG > Non-Brainstem pGBM
pGBM H3F3A mutation
ATRX, DAXX mutationATRX mutation
Peds > AdultsGBM > WHO I,II,III gliomasPeds > AdultsType of H3F3A mutation (G34R/V > K27M)
Key molecular alterations in pediatric glial tumors
1p/19q codeletion1p/19q codeletion
with polysomy “relative deletion”
No 1p/19q codeletion
Snuderl et al. Clin Cancer Res 2009.
Progression Free Survival Overall Survival
Anaplastic oligodendroglioma in adults (n=64)
1p and 19q deletions are infrequent in pediatric oligodendroglioma
Series N Age 1p del
19q del
1p/19q del
MGMT met
IDH1 mut
TP53 mut
Pollack et al., 2003
8 NA 1 2 NA NA NA NA
Raghavan et al. 2003
15 2-9 0 0 0 NA NA NA
11 10-18 2 0 3 NA NA NAKreiger et al., 2005
13 5-18 1 0 0 NA NA NA
Suri et al., 2011 7 3-18 0 0 0 5 0 0Creach et al., 2012
15 1-18 NA NA 2 NA NA NA
Total 69 1-18 4 (7.4%)
2 (3.7%)
5 (8.2%)
5 (71%) 0 0
Tumor type Molecular phenotype
Association
Oligodendroglioma
1p/19q codeletion Adults > Peds
Ganglioglioma BRAF V600E Peds > AdultsPXA BRAF V600E Peds = Adults
Mesenchymal histologyPilocytic astrocytoma
BRAF-KIAA1549 Tumor location/resectability (Cerebellar > Non-cerebellar)
DIPG 1q gain, 17p lossH3F3A, HIST1H3B mutations (K27M)
Peds > AdultsDIPG > Non-Brainstem pGBM
pGBM H3F3A mutation
ATRX, DAXX mutationATRX mutation
Peds > AdultsGBM > WHO I,II,III gliomasPeds > AdultsType of H3F3A mutation (G34R/V > K27M)
MacConaill et al. 2009
BRAF V600E in Ganglioglioma in Children
Schindler et al. 2011
Pediatric Ganglioglioma % BRAF V600E
MacConaill et al., 2009 57% (8/14)
Dougherty et al., 2010 50% (9/18)
Schindler et al., 2011 13% (3/24)
Total 36% (20/56)
Pediatric PXA
Schindler et al., 2011 78% (28/36) Dias-Santagata et al, 2011 57% (4/7) Total 74% (32/43)
BRAF V600E in Ganglioglioma and Pleomorphic Xanthoastrocytoma in Children < 18 years
• Initially described in melanoma, colon and papillary thyroid carcinoma• Vemurafenib (“V600E mutated BRAF inhibitor”)
– FDA approved for late-stage or unresectable melanoma (Aug 2011)
Tumor type Molecular phenotype
Association
Ganglioglioma BRAF V600E Peds > AdultsPXA BRAF V600E Peds = Adults
Mesenchymal histologyPilocytic astrocytoma
BRAF-KIAA1549 Tumor location/resectability (Cerebellar > Non-cerebellar)
Oligodendroglioma
1p/19q codeletion Adults > Peds
DIPG 1q gain, 17p loss
H3F3A, HIST1H3B mutations (K27M)
Peds > Adults
DIPG > Non-Brainstem pGBM
pGBM H3F3A mutation
ATRX, DAXX mutation
ATRX mutation
Peds > AdultsGBM > WHO I,II,III gliomas
Peds > Adults
Type of H3F3A mutation (G34R/V > K27M)Unlike in adults, EGFR amplification, PTEN deletion, IDH1 mutations
are rarely observed in pGBM.
`
Schwartzentruber et al., 2012
H3F3A mutations are exclusive to high grade tumors and occur in the pediatric setting.
H3F3A, ATRX, and DAXX mutations distinguish pediatric from adult GBM.
Tumor type Molecular phenotype
Association
Ganglioglioma BRAF V600E Peds > AdultsPXA BRAF V600E Peds = Adults
Mesenchymal histologyPilocytic astrocytoma
BRAF-KIAA1549 Tumor location/resectability (Cerebellar > Non-cerebellar)
Oligodendroglioma
1p/19q codeletion Adults > Peds
DIPG 1q gain, 17p loss
H3F3A, HIST1H3B mutations (K27M)
Peds > Adults
DIPG > Non-Brainstem pGBM
pGBM H3F3A mutation
ATRX, DAXX mutation
ATRX mutation
Peds > AdultsGBM > WHO I,II,III gliomas
Peds > Adults
Type of H3F3A mutation (G34R/V > K27M)H3F3A is located on chromosome 1q, a region of large-scale chromosomal gain in DIPG.
Adults Peds
Epigenome MGMT promoter methylation in adult GBM (associated with pseudoprogression s/p TMZ/RT and improved survival)
H3.3-ATRX-DAXX chromatin remodeling pathway in pGBM
Chromosome
1p/19q codeletion in adult OGD
1q gain, 17p loss in DIPG
Gene Adult AA with EGFR amplification behaves like GBM
EGFR amp, PTEN del are rare in pGBM/DIPG
PDGFRA amp in DIPGNucleotide IDH1 mutation (R132H) in
secondary GBM and LGG in adults
BRAF mutation (V600E) in ganglioglioma and PXA
Protein BRAF-KIAA1549 in cerebellar PAPARP-1 overexpression in DIPG
Tumor-derived Exosomes
• Exosomes are small membrane vesicles (30-100 nm) derived from luminal membranes of multivesicular bodies and released constitutively by fusion with cell membrane
• Released from tumor cells, exosomes mediate local and systemic cell communication through horizontal transfer of information, such as mRNA, miRNA, proteins, DNA
Electron microscopy of exosomes derived from U87 cells
Research questions:1. Can exosomes in peripheral blood of glioma patients serve as biomarkers of tumor progression? 2. Can exosomes in patient plasma reliably predict parent tumor mutational status in brain?
-IDH1 R132H mutation-BRAF V600E mutation
gDNA exoDNA- - ++DNase
3kb10kb
1kb
DNA is present in tumor cell derived exosomes. ExoDNA exists predominantly as methylated, single stranded DNA
Courtesy of Haiying Zhang and David Lyden
exoDNA-1+S1 nuclease
3kb10kb
1kb
-exoDNA-2
+ - gDNA
+ -
exoDNA
gDNA
Anti-5’metCytosine Anti-DNA
Acknowledgements
Neurosurgery• Jeffrey Greenfield, MD,
PhD• Michael Kaplitt, MD, PhD• Philip Stieg, MD, PhD
Pediatrics• David Lyden, MD, PhD
Neurosurgery• Philip Gutin, MD
Pathology• Jason Huse, MD, PhD
Neuroradiology• Andrei Holodny, MD