H3 K27M mutations are extremely rare in posterior fossa group A ependymoma.

Abstract

BACKGROUND:

Mutations in the tail of histone H3 (K27M) are frequently found in pediatric midline high-grade glioma's but have rarely been reported in other malignancies. Recently, recurrent somatic nucleotide variants in histone H3 (H3 K27M) have been reported in group A posterior fossa ependymoma (EPN_PFA), an entity previously described to have no recurrent mutations. However, the true incidence of H3 K27M mutations in EPN_PFA is unknown.

METHODS:

In order to discern the frequency of K27M mutations in histone H3 in EPN_PFA, we analyzed 151 EPN_PFA previously profiled with genome-wide methylation arrays using a validated droplet digital PCR assay.

RESULTS:

We identified only 1 case out of 151 EPN_PFA harboring the K27M mutation indicating that histone mutations are extremely rare in EPN_PFA. Morphologically, this single mutated case is clearly consistent with an ependymoma, and the presence of the K27M mutation was confirmed using immunohistochemistry.

DISCUSSION:

K27M mutations are extremely rare in EPN_PFA. Routine evaluation of K27M mutations in EPN_PFA is of limited utility, and is unlikely to have any bearing on prognosis and/or future risk stratification.

• Authors: Scott Ryall, Miguel Guzman, Samer K Elbabaa, Betty Luu, Stephen C Mack, Michal Zapotocky, Michael D Taylor, Cynthia Hawkins, Vijay Ramaswamy
• Journal: Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery (Childs Nerv Syst) Vol. 33 Issue 7 Pg. 1047-1051 (Jul 2017) ISSN: 1433-0350 [Electronic] Germany
• PMID: 28623522 (Publication Type: Case Reports, Journal Article)

Chemical References

• Histones
• Methionine
• Lysine

Topics

• Brain Neoplasms (diagnostic imaging, genetics)
• Child
• Ependymoma (diagnostic imaging, genetics)
• Histones (genetics, metabolism)
• Humans
• Lysine (genetics)
• Magnetic Resonance Imaging
• Male
• Methionine (genetics)
• Mutation (genetics)