Gene Expression Test Effectively Predicts Prostate Cancer Recurrence

A new gene expression test is designed to offer urologists an accurate and objective way of determining an individual's recurrence risk, beyond current clinical assessment techniques.

Myriad Genetics, Inc. (Salt Lake City, UT, USA) reported data that provides further clinical validation supporting its newest molecular diagnostic product, Prolaris, was presented in March 2010 at the 2010 Genitourinary Cancers Symposium in San Francisco (CA, USA). The abstract of the presentation entitled, "Cell Cycle Genes Predict Recurrence After Radical Prostatectomy,” by Gregory P. Swanson, M.D., from the University of Texas Health Science Center San Antonio (USA), and colleagues.

The study examined a well-described cohort of patients for which 10-year follow-up data were available following prostatectomy surgery. The study was carried out by Dr. Swanson and colleagues at the Scott and White Clinic (Temple, TX, USA) and demonstrated that the Prolaris molecular diagnostic test is a significant predictor of prostate cancer recurrence in training (p = 0.01) and validation cohorts (p = 0.00000006).

In patients with Gleason scores (the most widespread method of prostate cancer tissue grading) below 7, prostate-specific antigen (PSA) levels (protein produced by cells of the prostate gland) of less than 30 ng/mL and with disease confined to the prostate, the Prolaris test accurately identified those patients who had a low risk of disease recurrence with 95% certainty. In contrast, patients with a high-risk signature had a recurrence risk more than four-fold higher than those with a low-risk signature had. In the validation cohort, the test was also prognostic in patients with Gleason scores above 6, PSA levels of greater than 30 ng/mL and with evidence of disease outside the prostate (p = 0.0026).

"These exciting scientific findings provide further support of our new Prolaris molecular diagnostic test and should have significant clinical impact for prostate cancer patients and their physicians,” commented Jerry Lanchbury, Ph.D., chief science officer at Myriad Genetics. "We believe that the Prolaris diagnostic has the potential to transform the care of prostate cancer patients, and that future studies that focus on patients who have not yet undergone surgery will further extend the test's potential clinical utility.”

In the United States, approximately 80,000 men undergo a radical prostatectomy (removal of the prostate gland and some surrounding tissue) each year. Approximately 35% of those men will eventually have a biochemical recurrence indicating the return of their cancer.

Using the test, patients at higher risk of recurrence are candidates for more intensive screening and therapeutic strategies given the aggressiveness of their cancers. Patients at lower risk of recurrence are good candidates for "watchful waiting.”

Prolaris consists of a panel of 46 genes, most of which are involved in cell cycle progression. The test examines standard prostate tumor material available to pathologists to estimate quantitatively the risk of cancer recurrence in patients who have undergone a radical prostatectomy. For the first time, Prolaris provides clinicians with a direct molecular measure of a prostate tumor's capacity to divide and grow by examining genes that drive tumor growth at the molecular level. In the United States alone, 80,000 prostate cancer patients may benefit from the Prolaris risk recurrence assessment each year.

Myriad Genetics is a molecular diagnostic company focused on developing and marketing novel predictive medicine, personalized medicine, and prognostic medicine products.

Related Links:
Myriad Genetics
University of Texas Health Science Center San Antonio
Scott and White Clinic