LISBON, June 14 (Xinhua) -- A Portuguese research team discovered a mechanism that controls the spread of glioblastoma, a form of malignant brain tumor, the Gulbenkian Institute of Science (IGC) said in a statement on Friday.

Glioblastoma, with a prevalence in the population estimated at one per 100,000 inhabitants in Europe, is the most aggressive brain cancer with the worst prognosis because the tumor's ability to invade the surrounding brain tissue makes it difficult to remove by surgery, and it often reappears after surgery, the statement said.

"The invasiveness of this type of tumor is such a serious matter that many researchers are dedicated to trying to understand what mechanisms allow glioblastoma cells to invade the brain tissue around them," said Diogo Castro, who led the research team.

Zeb1, a molecule known to be involved in the process of glioblastoma invasion, belongs to an important group of regulatory molecules called transcription factors. The perform within the cells is like a conductor who directs an orchestra, telling the musicians when to start playing, said Pedro Rosmaninho, another researcher in the team.

According to the statement, the finding showed how the Zeb1 molecule "plays its part inside the cancer cells when it allows them to be able to invade the healthy brain tissue around them," thus confirming the role of the molecule in glioblastoma.

The researchers used cell cultures created from human biopsies and databases that contained the genetic profile of hundreds of glioblastoma tumors to map the genes that are regulated by Zeb1 in the human genome.

The experiment showed that the molecule orchestrates important changes in the properties of cancer cells "by playing a dual role," that is, their presence can simultaneously "turn on" or "turn off" a large number of genes. This ends up altering the interaction between the cancerous cells, being able to infiltrate in the cerebral tissue in which the tumor develops.

"The better we perceive how glioblastoma tumor cells invade the surrounding tissues, the closer we will be to one day finding effective therapies that can disrupt this process," said Castro.

The research was conducted at the IGC in collaboration with researchers from Germany's Edinger Institute of Neurology and Canada's McGill University.