NEW YORK (GenomeWeb News) – Gene silencing in tumors by DNA methylation may be an effective biomarker for prostate cancer recurrence after surgery, according to research being presented at a conference today.
Researchers at Oregon Health and Science University’s Cancer Institute evaluated the DNA methylation state of more than a dozen suspicious genes in prostate cancer tissue samples taken from patients during prostatectomies, surgery to remove all or part of the prostate gland. They found that prostate cancer recurrence was linked to silencing of one of these genes, called CDH13. Joshi Alumkal, an OHSU oncologist and researcher, is scheduled to present the findings at the American Society of Clinical Oncology’s Genitourinary Symposium in San Francisco today.
Nearly 220,000 people were diagnosed with prostate cancer last year, and more than 27,000 people died of the disease. In an effort to better understand what causes the prostate cancer to return in some men after surgery, Alumkal and his team used a PCR-based assay called methylation-specific PCR to assess the methylation state of 15 genes known to influence prostate cancer in tissue samples from 151 research subjects — a third of whom had prostate cancer recurrence within five years of their surgery.
They reportedly found specific changes in DNA methylation that could portend cancer recurrence. In particular, they focused on CDH13, a gene coding the protein cadherin 13, which seems to play a role in cell-cell adhesion. In this study, patients whose tumors had the CDH13 gene silenced were about five times more likely to get prostate cancer again, perhaps because turning off the gene increases the likelihood that tumors will metastasize or spread to other parts of the body.
Though the work needs to be replicated in a larger group of people, the team is confident that such PCR-based methylation studies hold promise for assessing prostate cancer recurrence risks.
“In the clinic, those of us who care for patients with prostate cancer look at the pathology report and PSA blood test to determine how a patient will do after surgery and how aggressive their tumors will be. However, these tools are not perfect,” Alumkal said in a statement. “We were searching for a biomarker to identify patients for whom these clinical predictors would improve upon our existing tools and would allow us to make more accurate predictions about tumor behavior down the road.”