Researchers at UT Southwestern Medical Center have discovered a cell-signaling mechanism instrumental in the most common brain cancer in adults.

The study, published in the journal Cancer Research, opens an avenue to develop therapeutic drugs to target the epidermal growth factor receptor genes that play a major role in the development of deadly brain tumors.

The median survival of patients with glioblastoma multiforme ( GBM ), a cancer of the supportive tissue of the brain, currently is about one year after diagnosis with the best treatments available, said Amyn Habib, at UT Southwestern and the senior author of study.
Glioblastoma multiforme, which accounts for 60 percent of brain tumors in adults older than 50 years, can infiltrate the brain extensively and sometimes becomes enormous before turning symptomatic.

Researchers have known for years that tumor cells proliferate out of control by a mechanism characterized by an abnormally high number of copies of the epidermal growth factor receptor gene ( EGFR ).
This overexpression of EGFR is a striking feature of glioblastoma multiforme, present in 40 percent to 50 percent of tumors and results in an uncontrolled multiplication of both normal EGFR and a mutant form called EGFRvIII.

While studying human brain tumor tissue and human brain tumor cells from cell lines grown in the laboratory, Habib and his colleagues discovered that EGFRvIII generates a unique pattern of signaling ( distinct from normal EGFR ) that causes brain cancer cells in glioblastoma multiforme to grow and multiply unchecked.

" The better we understand the signaling mechanisms of the normal and the mutant EGFR, the better we can manipulate or control them," Habib said. " Our findings suggest that you have to target both the mutant and the normal EGFR based on the mechanism we described."

Current standard treatment of glioblastoma multiforme consists of surgical removal of the tumor, followed by radiation and chemotherapy.

Source: UT Southwestern Medical Center, 2006


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