Microscopic examinations of tumor tissue (histology) make it possible to differentiate several subtypes of brain cancer. However, analyses of tumor genomes and investigations at molecular level have shown that tumors of similar histology can vary considerably in their biological behavior and their response to anticancer drugs.

Marcel Kool, who is a staff scientist at KiTZ and a group leader at DKFZ's Pediatric Neurooncology Division, explains: "This means that a new targeted anticancer drug that is very effective in one patient may fail completely in another patient even though the tumors look very similar under the microscope. Since every ineffective therapy is a risk for the young patients and may also be extremely stressful for their minds and bodies, we need model systems that we can use to test the effectiveness of new therapy approaches in tumors with specific characteristics at molecular level before applying them in children." Mouse transplant systems have been very successfully used as models in cancer medicine for adults because they offer a natural environment for brain tumors. In the artificial environment of a culture medium, the tumor cells most often fail to grow, or if they do, they show a completely different behavior than they do in the patient.

"In collaboration with our colleagues from the Seattle Children's Hospital, the University of Washington, and the Fred Hutchinson Cancer Research Center in Seattle, USA, we have generated and characterized 30 tumor models representing 14 subtypes of pediatric brain tumors for the new biobank," said Sebastian Brabetz, a KiTZ scientist and first author of the publication. He added: "It has become evident that our tumor models reflect the brain tumors in patients very well. Thus, we can expect highly meaningful results from tests of novel substances in these tumor models." The scientists plan to further expand the biobank over the next few years to represent as many brain tumors as possible including rare subtypes.

A biobank with worldwide access

The working groups from Heidelberg and Seattle have made the tumor models and the corresponding data (r2platform.com/pdxexplorer) available in the biobank (http://www.btrl.org/) for the whole scientific community in order to advance cancer research worldwide. For translational oncology, the biobank is an important element bridging the gap between basic research and clinical application. In addition, it is an important resource for further research in cancer medicine from which ultimately all patients, children as well as adults, can benefit greatly. Gathering models of pediatric brain tumors in a biobank that is accessible for all scientists around the globe is a first and important step within a project called ITCC-P4 (Innovative Therapies for Children with Cancer - Pediatric Preclinical Proof-of-concept Platform), which was launched in 2017. Stefan Pfister, Director of the Preclinical Program at KiTZ and also a senior physician at Heidelberg University Hospital, explains the relevance of this biobank in the worldwide battle against cancer in children: "Among the many innovative compounds that have usually been developed to treat cancer in adults, it is very challenging to identify those that are also active against pediatric cancers. Within the ITCC-P4 project, which is undertaken as a joint venture with pharmaceutical companies, the European Union therefore supports the development of systems that make it easier and faster to identify effective cancer medications for children."

These results were published in Nature Medicine.