A two-tier system in brain tumors

From a large-molecular genetic study on the cerebellum was seen that the second most common type of malignant brain tumor in children is the ependymoma. An international team of researchers has discovered that the second most common type of malignant brain tumor in children is the ependymoma. The discovery is part of a large-molecular genetic study of ependymomas of the cerebellum. Presented in the journal Cancer Cell, the study reveals that, on the basis of their genetic material anomalies, cerebellar ependymomas are classified into two distinct subgroups: group A ependymomas and ependymomas of the group B. The first negative characteristics, while the latter have a positive prognosis.

The ependymoma emerges from precursor cells of the central nervous system tissue that lines the cavities of the brain. The treatments to fight this cancer get different results. The conditions of some patients may be improved with surgery and radiotherapy, which help to stop the growth of the tumor, while others are suffering from cancers that move quickly and seriously. About 50% of children with cancer have forms that continue to grow, and some of them die.

“I am especially patients with a severe course in urgent need of better therapies,” explains Dr. Stefan Pfister, a researcher at the German Center for Cancer Research (DKFZ) and Heidelberg University Hospital, who collaborated with colleagues from Canada, Italy, Poland, Russia and the United States.

The team assessed the activity of individual genes in 583 samples of tissue. They studied the genetic material for losses or additions of entire segments of deoxyribonucleic acid (DNA). The researchers conducted independent evaluations of the two groups of cancer and the results were then validated on tissue samples of a third group. According to the team, this allowed them to obtain valid results.


They point out that the tumors of Group A are relatively few losses or additions of gene segments. But it enabled a number of genes that act on signaling pathways of cancer. On the one hand, group A tumors often metastasize, usually causing the death of patients. The tumors of group B, however, offer more hope for patients, although the genome of these tumor cells is not very stable. Experts say the additions are typical of large segments of chromosomes 9, 15 and 18, and losses of chromosomes 6 and 22.

“The genetic differences between these two types are so obvious that we should speak of two different diseases that can also result from different original cells,” said Dr. Pfister.

The German group intends to pursue this matter further. They will assess the group ependymomas To discover which of the genetic mutations are the so-called drivers, or mutations that activate the production of cancer cells. Further work will help researchers identify potential targets for more effective drugs able to fight tumors of group A.

It should be noted that researchers have developed targeted drugs for a variety of signaling pathways that are overactive in ependymomas of group A. Clinical trials are now testing these drugs for other cancers. The team does know that many of these substances could probably be vital for the treatment of ependymomas.