A better option for early prostate cancer detection

Written by 
Deborah Robison
PSA test

The most widely used test to screen men for prostate cancer measures levels of prostate-specific antigen (PSA) in urine, but it has a high false-positive rate. According to the American Academy of Family Physicians, about 70 percent of men with elevated PSA are found upon biopsy not to have prostate cancer.

Ranjan Perera, Ph.D., associate professor and scientific director of the Analytical Genomics and Bioinformatics core at SBP, is seeking to create a more sensitive and specific test for prostate cancer by measuring multiple biomarkers in urine. By combining transcriptomics and metabolomics, the new process provides signatures of both RNA and metabolites to produce a more accurate diagnostic.

The need for a more precise test was underscored last week when the U.S. Preventive Services Task Force, an independent panel of experts, broadened their prostate cancer screening guidelines. The new recommendations encourage men ages 55 to 69 to "make an individualized decision about prostate cancer screening with their clinician," an update from the previous recommendation for no routine screening at any age.

Prostate cancer is the second most common form of cancer among men in the U.S., affecting one in seven men and causing nearly 27,000 deaths per year.

The tests Perera aims to develop are noninvasive—an approach often referred to as “liquid biopsy.” Most liquid biopsy tests measure circulating tumor cells or free-floating DNA from cancer cells, as tremendous progress has been made in developing methods of analyzing that DNA to identify mutations that drive a tumor’s growth and help guide treatment decisions.

Liquid biopsies tests that analyze molecules in urine have also been commercialized, demonstrating the feasibility of Perera’s approach. Currently available diagnostics identify EGFR, BRAF and KRAS mutations that are associated with various cancers and kidney disease.

“Because of the complexity of prostate cancer, we do not believe any single biomarker, for example, PSA or PCA3, will be a magic bullet for diagnosis,” says Perera. “We are investigating multiple markers to have better prediction value.”