Lawson Health Research Institute, Memorial Sloan Kettering Cancer Center, the Royal Marsden and Epic Sciences conducted an international mutual study which discovered a novel blood test that can foresee advanced prostate cancer patient response to particular treatments, resulting in better survival.

A liquid biopsy test introduced by molecular diagnostics company Epic Sciences was used, that evaluates circulating tumor cells (CTCs) in blood collected from patients suffering from advanced prostate cancer who are contemplating a shift from hormone-targeting therapy to chemotherapy. CTCs are cancer cells that depart from a tumor and flow into the bloodstream and penetrate other parts of the body, causing metastasis.

The test looks for a protein called AR-V7 in the cell nucleus of the patient's CTCs. The research team aspired to conclude whether the existence of this protein predicted which treatment would result in maximum prolongation of a patient's life. They discovered that patients who tested positive for the protein gave the best response to taxane-based chemotherapy whereas, those who tested negative responded best to hormone-targeting therapy with androgen-receptor signaling (ARS) inhibitors, the two most commonly used drug classes to manage advanced prostate cancer.

"The study focused on a critical decision point when patients and their oncologists are choosing what therapy to pursue next," says Dr. Alison Allan, a scientist at Lawson and Chair, Department of Anatomy & Cell Biology at Western University's Schulich School of Medicine & Dentistry. "We are addressing a critical unmet need by validating that a blood test or liquid biopsy can be used to select a therapy most likely to extend a patient's life."