Gene Mutations That Cause Childhood Brain Cancer Identified

Researchers have discovered eight similar genes, with strong links between
H3K9 methylation and EHMT1, L3MBTL3, L3MBTL2, SCML2, JMJD2C, JMJD2B and MYST3, that, when mutated, appear to be responsible for medulloblastoma – the most common of childhood brain cancers. According to Dr Christine Williams, Director of Research Programs, Canadian Cancer Society Research Institute, this discovery may help researchers develop better, more targeted treatments for children.


It took researchers 3½ years, where they analyzed and interpreted data from more than 200 tumour samples. These samples came from children all over the world. Medulloblastoma, a term first used by Bailey and Cushing in 1925, describes a series of malignant tumours found in the cerebella of children. These tumours have the propensity to spread throughout the Central Nervous System. Medulloblastoma is more common in children between the ages of three and eight and is particularly deadly among babies under 18 months of age.

Below is an excerpt from the study which was published March 8 in the online edition of the journal Nature Genetics. http://www.nature.com.ezproxy.library.uq.edu/ng/index.html

“We used high-resolution SNP genotyping to identify regions of genomic gain and
loss in the genomes of 212 medulloblastomas, malignant pediatric brain tumors.
We found focal amplifications of 15 known oncogenes and focal deletions of 20
know tumor suppressor genes (TSG), most not previously implicated in
medulloblastoma. Notably, we identified previously unknown amplifications and
homozygous deletions, including recurrent, mutually exclusive, highly focal
genetic events in genes targeting histone lysine methylation, particularly that
of histone 3, lysine 9 (H3K9). Post-translational modification of histone
proteins is critical for regulation of gene expression, can participate in
determination of stem cell fates and has been implicated in carcinogenesis.
Consistent with our genetic data, restoration of expression of genes controlling
H3K9 methylation greatly diminishes proliferation of medulloblastoma in vitro.
Copy number aberrations of genes with critical roles in writing, reading,
removing and blocking the state of histone lysine methylation, particularly at
H3K9, suggest that defective control of the histone code contributes to the
pathogenesis of medulloblastoma.”

For more information please follow the following links:

http://www.sciencedaily.com/releases/2005/10/051031080129.htm

http://www.cancerbackup.org.uk/cancertype/brain/typesofbraintumour/medulloblastoma

http://www.sciencedaily.com/releases/2005/10/051031080129.htm