Craniopharyngiomas occur in less than one in 100,000 people. They are slow-growing tumors that don't metastasize, but they can cause severe complications, including headaches, visual impairment, hormonal imbalances, obesity and short stature. Even with expert neurosurgery, it is difficult to completely remove the tumors without damaging normal structures, and the tumors often recur.
The investigators were surprised to find that the single mutated BRAF gene was the sole driver of 95 percent of the papillary craniopharyngiomas they analyzed with whole-exome DNA sequencing. "We were really surprised to find that something as simple as a BRAF mutation by itself, rather than multiple mutations, is what drives these tumors," said Santagata.
One scenario, should the inhibitors prove successful in halting or reversing growth of the tumors, would be to test the drugs preoperatively with the aim of shrinking the tumor so less radical surgery would be needed, said Santagata.
A different mutation, in a gene called CTNNB1, was identified as the principal abnormality in the pediatric tumors, according to the report. This mutation causes overactivity in the beta-catenin molecular growth-signaling pathway. Unlike with the BRAF mutation, drugs that inhibit the CTNNB1 abnormality have not yet reached the clinic, but several groups are working on them, Santagata said.
|Contact: Irene Sege|
Dana-Farber Cancer Institute