Gene-Based Urine Test Improves Accuracy of Prostate Cancer Diagnosis

The test determines the presence of a genetic marker for prostate cancer, prostate cancer gene 3 (PCA3).

Called Progensa PCA3, the test has a number of advantages over existing diagnostic tools. Prostate-specific antigen (PSA) can be elevated for reasons not related to prostate cancer, and as a result, PSA testing produces many false-positive results, which can burden patients and the healthcare system. In contrast, the genetic marker PCA3 is elevated only in cancerous prostate tissue, making it a more specific indicator of cancer than PSA, potentially reducing the number of unnecessary biopsies.

The study of 570 men found that men with a PCA3 score of less than five showed a positive biopsy rate of 14%; however, a PCA3 score greater than 100 showed a 69% biopsy positive rate. Results were similar regardless of a patient's PSA levels or whether they had undergone repeat biopsies.

Co-author of the study, Dr. Jack Groskopf, director of oncology research and development at Gen-Probe Inc. (San Diego, CA, USA) commented, "We found that the percent of biopsy-positive men identified directly increased with the PCA3 score. We also confirmed that the PCA3 score was independent of prostate size; this is important because PSA levels can be elevated in men who have enlarged prostates due to non-cancerous conditions.”

The study expands on findings from a previous study conducted by Dr. Leonard Marks, of the Urological Sciences Research Foundation, published in the March 2007 issue of Urology.

Progensa PCA3 is the first CE-Marked test to use the presence of PCA3 to predict prostate cancer, and can be used in conjunction with current tests to confirm diagnosis. PCA3 is overexpressed, relative to benign cells, by 60- to 100-fold in more than 90% of prostate tumors. DiagnoCure, Inc. (Quebec, Canada) is the exclusive worldwide licensee for all diagnostic and therapeutic applications of the gene. Gen-Probe acquired exclusive worldwide diagnostic rights to the PCA3 gene from DiagnoCure in 2003. The test is marketed across the European Union.


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