Intercellular heterogeneity of expression of the MGMT DNA repair gene in pediatric medulloblastoma.

DNA methylation and epigenetic inactivation of the O6-methylguanine methyltransferase (MGMT) gene induces MGMT deficiency, reducing the tumor cell's DNA repair capacity and increasing its susceptibility to alkylating chemotherapeutic agents. Consequently, adult patients whose tumors are deficient in MGMT have better outcomes with alkylator chemotherapy, and MGMT methylation has been proposed as a screening marker of deficient tumors. In order to test the feasibility of this approach for medulloblastoma, a common brain tumor in children, we determined the methylation status, mRNA expression pattern, and protein expression of MGMT in a panel of clinical specimens.

Hypothalamic hamartoma secreting corticotropin-releasing hormone. Case report.

The authors describe a unique case of a 2-year-old boy with a hypothalamic hamartoma secreting corticotropin-releasing hormone (CRH). The patient presented with a history of behavioral disturbances progressing over 12 months. His neurological status was intact.

Advances in the diagnosis, molecular genetics, and treatment of pediatric embryonal CNS tumors.

Embryonal central nervous system (CNS) tumors are the most common group of malignant brain tumors in children. The diagnosis and classification of tumors belonging to this family have been controversial; however, utilization of molecular genetics is helping to refine traditional histopathologic and clinical classification schemes. Currently, this group of tumors includes medulloblastomas, supratentorial primitive neuroectodermal tumors, atypical teratoid/rhabdoid tumors, ependymoblastomas, and medulloepitheliomas.

Hypermethylation of HIC-1 and 17p allelic loss in medulloblastoma.

Medulloblastoma is the most common malignant brain tumor in children. Chromosome arm 17p13.3 is reduced to homozygosity in 35-50% of medulloblastomas,making it the most frequent genetic alteration in these tumors.