Genetic Abnormality Discovered for Brain Cancer

A chromosomal abnormality in children with a deadly form of brain cancer has been discovered, and is linked with a poorer chance of survival.

The discovery could potentially lead to a new diagnostic test to allow doctors to identify youngsters who are at the highest risk associated with an ependymoma tumor and may need aggressive life-saving treatments.

A study led by experts at University of Nottingham (UK) as part of a European collaboration focused on looking at abnormal copies of chromosomes in the cells of ependymoma tumors and aimed to establish whether it was associated with a worse outlook for children suffering from the disease. The scientists assessed the results from 147 brain ependymomas in young UK and French children who received tumor surgery followed by chemotherapy and older European children who received tumor surgery followed by radiotherapy.

In tumor cells, the number of chromosomes can vary significantly from the normal cell numbers and in ependymoma a frequent finding from biological studies is increased copies of chromosome number 1, specifically increased numbers of the long arm of chromosome 1. This abnormality is termed 1q copy number gain. Copy number gain of 1q in the ependymoma cells from each of the 147 patients was assessed using a technique called fluorescence in situ hybridization (FISH) in which pieces of DNA called probes are made in the laboratory containing a fluorescent dye. This enables the tumor cells to be seen down a fluorescent microscope. In the project, the scientists used a green probe (Vysis; Des Plaines, IL, USA) that bound to a region within chromosome 1q of the tumor cells, called 1q25.

The team then linked which of the ependymomas had increased copies of the 1q25 probe in their cells to corresponding patient data to work out whether increased copy number gain was associated with a worse survival rate. The authors advocate the prospective evaluation of 1q25 gain as a prognostic marker in forthcoming large international clinical trials of pediatric intracranial ependymoma, both independently and integrated with tumor resectability. Upon successful validation, 1q25 gain could be incorporated into future clinical trial design in order to improve risk stratification for children diagnosed with this tumor.

Richard Grundy MBChB, PhD, professor of Pediatric Neuro-oncology and Cancer Biology at Nottingham said, "We are now hoping that these findings are reproduced in other studies currently underway in other countries, including the USA. If their results match ours, then the presence of 1q25 copy gain in childhood ependymoma could be introduced into future international treatment planning as a new marker of poor outcome which will in turn define treatment.” The study was published in the April 1, 2012, edition of the journal Clinical Cancer Research.

Related Links:
University of Nottingham
Vysis Inc.