U.S. and Canadian researchers identified a biomarker that predicts which
prostate cancer patients are likely to have their cancer recur or spread.
Co-investigators Andries Zijlstra, an assistant professor at Vanderbilt
University Medical Center, and John Lewis, an associate professor at the
University of Alberta, said some prostate cancer spreads slowly and does not
lead to serious symptoms, while in other patients the cancer metastasizes to
other parts of the body and is fatal. Cancer researchers have been searching for
biomarkers that indicate which patients should be treated aggressively and which
patients can be followed through active surveillance, or watchful waiting.
Zijlstra and colleagues investigated the protein CD151 that facilitates the
migration of cancer cells. In prostate cancer cell lines, they discovered that
CD151 is free from its normal adhesion partner -- integrin -- another protein
that allows a cell to stick to the surrounding tissue. This form of CD151 called
"CD151free" proved to be functionally important in cancer.
"It was a big surprise that some of this CD151 protein was now free of that
partner and it turns out that it only occurs when a cancer is formed," Zijlstra
said in a statement. "What's so novel about this discovery is we're not talking
about changing protein expression, which is what we traditionally see. We're
talking about a protein that changes its molecular state and detection of that
molecular state is an indication of disease progression."
In collaboration with Lewis and colleagues in Alberta, the group looked at
tissue samples from 137 patients treated for prostate cancer in Canada over the
past 12 years.
The team determined that if patients tested positive for CD151free their cancer
recurred and spread earlier than patients without any detectable CD151free.
"Patients who tested positive for the biomarker developed metastasis an average
of 10 years earlier than those who tested negative," Lewis said.
The findings were published online ahead of the print edition of Cancer