APPLICATION OF CANCER PROCOAGULANT AS AN EARLY DETECTION TUMOR-MARKER

Background. In spite of many advances in the analytical reagents (anti bodies), analytical systems, and the clinical application of tumor mar kers, the present markers do not detect early stage cancer. Preliminar y data with an antigen specific to tumor tissue, cancer procoagulant ( CP), suggest its possible role in the detection of early stage cancer. This study was aimed at determining the clinical use of CP as an earl y stage tumor marker. Methods. An improved enzyme-linked immunosorbent assay (ELISA) was developed to measure CP concentration in serum. A p anel of 817 blinded serum samples were examined from three groups of p eople: 573 cancer, 106 benign, and 139 normal.Results. The sensitivity of all samples analyzed from cancer patients was 80%. The CP ELISA wa s able to detect ovarian, colon, and kidney cancer at a sensitivity gr eater than 85%; breast, prostate and small cell lung cancer was detect ed at a sensitivity of 80-85%. Particularly interesting was the observ ation that early stage cancers, regardless of site, were detected effe ctively. In some groups, the CP assay correctly identified 100% of the patients with stage I and II cancer. The assay was able to identify c orrectly noncancer patient sera at a specificity of 83% for those with benign disease and 82% for the normal individuals. Conclusions. The C P assay has potential as an aid in diagnosing early stage malignancies and thereby may significantly improve the survival rate of cancer pat ients.