Hepsin is a Type II Transmembrane Serine Protease which was first identified in human liver and hepatoma cell lines in 1988 (Leytus, 1988). Hepsin has been shown to be overexpressed in multiple cancers including liver, ovarian, renal, and breast cancer. Hepsin is also overexpressed in prostate cancer, where it has been shown to be an active participant in the metastatic processes. Hepsin seems to be a good marker for prostate malignancy as it is overexpressed in PIN and prostate carcinomas, but has very low or no expression in benign prostatic hyperplasia (BPH) or normal prostate tissue (Goel, 2011). Hepsin expression peaks in Prostatic Intraepithelial Neoplasia (PIN), a pre-cancerous condition, or early stage prostate disease and then reduces as the cancer progresses to metastasis (Vasioukhin, 2004). In a mouse model, Hepsin promoted prostate cancer progression and metastasis by causing disorganization of the basement membrane which led to metastasis to the liver, lung, and bone (Klezovitch, 2004). Targeted Hepsin inhibition has been shown to suppress invasive tumor growth (Li, 2009) and block bone metastasis in prostate cancer (Tang, 2004).
Stage I Diagnostics, Inc. has developed a proprietary Hepsin ELSIA assay for the purpose of diagnosing aggressive prostate cancer at its earliest stages. In order to validate the assay in a clinical setting, Stage I partnered with Arkansas Urology, the largest urology practice in the state of Arkansas, for a clinical trial in which blood would be drawn at the time of biopsy to test for measurable levels of Hepsin. Preliminary results from this study show that Hepsin levels can identify patients who are good candidates for Active Surveillance (low-grade cancer) with 96% specificity and 82% NPV. Based on these results, our Hepsin test is currently being utilized to help determine if a prostate cancer patient is a good candidate for active surveillance, as opposed to more aggressive treatments. Ultimately, we feel our panel of tests, along with Hepsin, will be able to determine if aggressive prostate cancer is developing at the earliest stages of the disease. At Stage I Diagnostics, we are working diligently to improve the standard of care for prostate cancer patients by reducing unnecessary procedures and costs through better diagnosis of the disease.