Posted January 24, 2013
Dr. Amin I. Kassis, Harvard University
The prostate specific antigen (PSA) is the primary marker used for the early detection of prostate cancer. However, the high frequency of false-positives and false-negatives and the inability to differentiate between aggressive and non-lethal forms of cancer has led to extensive over-treatment, making improved methods for the early detection of prostate cancer greatly needed. Dr. Amin I. Kassis and his research group at Harvard University received a FY08 Idea Development Award to support their development and testing of a new, non-invasive genomic assay for the early detection of prostate cancer using blood samples.
The genomic assay relies on the presence of tumor cells that have been shed into the body's circulatory system, called circulating tumor cells (CTCs). Since most of these CTCs undergo programmed cell death, Dr. Kassis hypothesized that the removal of such cells from circulation by phagocytic white blood cells will lead to the expression of prostate cancer-specific signatures by these cells. The subsequent assay developed by Dr. Kassis' group was able to successfully differentiate, with 100% accuracy, between mice with prostate cancer and those without. Furthermore, since these gene signatures were undetectable in the blood of mice that had their tumors surgically removed, the assay can readily and accurately monitor therapeutic efficacy.
Dr. Kassis currently has multiple U.S. and world-wide patents pending for the new assay. Additional funding support from an NIH Challenge Grant enabled him to show that the assay is able to detect the gene signatures in cancer patients with high accuracy (>99%). The technology has now been licensed to Cell MDx, Inc., through which the diagnostic potential of the assay will be tested in larger numbers of prostate cancer patients. Dr. Kassis also noted, "We strongly believe that the blood assay we have been developing will have an unprecedentedly high impact on, and contribute significantly to, the goal of early detection and eradication of prostate cancer in the U.S. and worldwide. I am most grateful to the DoD PCRP for their willingness to fund a highly risky idea. Without their support, I seriously doubt that this technology's potential could have been assessed and established."
Diagram of assay used to differentiate gene expression profiles of white blood cells that have or have not cleared (via phagocytosis) prostate cancer cells from the circulation.