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pediatric malignant astrocytoma

Tuesday 2 February 2010

BRAF mutations

- BRAF is a frequent mutation target in pediatric astrocytomas, with distinct types of BRAF alteration occurring in grade 1 versus grade 2 to 4 tumors.

- BRAF-V600E mutation seems to define a subset of malignant astrocytomas in children, in which there is frequent concomitant homozygous deletion of CDKN2A. (20068183)

DNA copy number aberrations (CNA)

- Genomic amplifications of 10-fold or greater are restricted to grade 3 and 4 astrocytomas

  • MDM4 (1q32 amplification)
  • PDGFRA (4q12 amplification)
  • MET (7q21 amplification)
  • CMYC (8q24 amplification)
  • PVT1 (8q24 amplification)
  • WNT5B (12p13 amplification)
  • IGF1R (15q26 amplification)

- Homozygous deletions among grade 2 to 4 tumors

  • CDKN2A (9p21 deletion)
  • PTEN (10q26 deletion)
  • TP53 (17p3.1 deletion)

- BRAF rearrangements

References

- Oncogenic BRAF mutation with CDKN2A inactivation is characteristic of a subset of pediatric malignant astrocytomas. Schiffman JD, Hodgson JG, VandenBerg SR, Flaherty P, Polley MY, Yu M, Fisher PG, Rowitch DH, Ford JM, Berger MS, Ji H, Gutmann DH, James CD. Cancer Res. 2010 Jan 15;70(2):512-9. PMID: 20068183