An MRI depicts a glioblastoma (center white mass) before treatment with the drug erlotinib (A) and after (B).
Scientists at the University of California, San Diego School of Medicine and UC San Diego Moores Cancer Center, in collaboration with colleagues in Boston and South Korea, say they have identified a novel gene mutation that causes at least one form of glioblastoma (GBM), the most common type of malignant brain tumor.
Past studies have identified epidermal growth factor receptor (EGFR) as a common genetically altered gene in GBM, though the cause or causes of the alteration is not known. The research team, led by scientists at the Dana-Farber Cancer Institute in Boston, analyzed the GBM genomic database, ultimately identifying and characterizing an exon 27 deletion mutation within the EGFR carboxyl-terminus domain (CTD). An exon is a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.
“The deletion mutant seems to possess a novel mechanism for inducing cellular transformation,” said Frank Furnari, PhD, associate professor of medicine at the UC San Diego School of Medicine and an associate investigator at the San Diego branch of the Ludwig Institute for Cancer Research.
The study researchers determined that cellular transformation was induced by the previously unknown EGFR CTD deletion mutant, both in vitro and in vivo, and resulted in GBM in the animals. The researchers then turned to testing a pair of approved drugs that target EGFR: a monoclonal antibody called cetuximab and a small molecule inhibitor called erlotinib.