Life expectancy of people with aggressive brain cancer may be easier to
determine with a new method under development at the University of Alabama at
Birmingham, researchers say.
The UAB researchers found that patients with an overactive version of a
specific enzyme live less than half as long as those with a less active version.
This overactive enzyme can help predict how resistant the brain cancer will be
to chemotherapy, and also help doctors arrive at treatment recommendations, the
In conducting the study, published in the journal PLoS ONE,
the researchers examined tumours from 84 patients with a form of brain cancer
known as glioblastoma multiforme (GBM). This deadly and aggressive cancer
quickly becomes resistant to available treatments. With a combination of
surgery, radiation and the chemotherapy drug temozolomide, patients with this
form of brain cancer typically survive an average of 12 to 15 months.
The study revealed, however, that 25% to 30% of the patients whose tumour
cells had an overactive version of an enzyme known as cytochrome c oxidase (CcO)
live less than half as long as patients with a less active version.
"Our study reports for the first time the role of [CcO] as a prognostic
marker in GBM patients' tumour tissues," study leader Corinne Griguer, an
associate professor of neurosurgery in the UAB School of Medicine, said in a
university news release. "High CcO activity comes with a 25-fold increase in
risk of death."
The researchers said patients with the overactive enzyme lived for an average
of six months. Those with a less active version lived for 14 months. Examination
of a second group of glioblastoma multiforme patients from Europe confirmed
their findings, the researchers said.
They concluded that tumour cells with increased CcO activity generate more
energy and are more resistant to chemotherapy. The overactive enzyme also
interferes with a protein, called cytochrome c, that triggers the
self-destruction of cells infected or damaged by diseases such as cancer. When
this happens, cancer cells can survive an abnormally long time.
But the researchers aren't stopping with this finding. "Giving some GBM
patients bad news about their prognoses without also giving them better
treatment options doesn't seem right to me," said Griguer, noting that the team
is experimenting with another enzyme to try to predict patients' survival
benefit from the chemo drug temozolomide.
"Our ultimate goal is to use the same mechanism that predicts shorter
survival in some to design drugs that target cells not killed right away by
chemotherapy," she said.
The US National Institutes of Health provides more information on brain
(Copyright © 2013 HealthDay. All rights