Human kallikrein 6 (zyme/protease M/neurosin): A new serum biomarker of ovarian carcinoma

Background: There is an urgent need for discovery and validation of new ser um biomarkers for ovarian carcinoma. Early diagnosis of ovarian cancer with serologic analysis may improve clinical outcomes through administration of effective treatment. Human kallikrein 6 (hK6, encoded by the KLK6 gene) is a serine protease of the kallikrein gene family. Recently, we were able to develop an immunofluorometric procedure for the quantitative measurement o f hK6 in biologic fluids, including serum. Methods: We have used an hK6-specific immunofluorometric assay to quantify hK6 protein in a large number of serum samples from normal individuals, as well as from patients with various malignancies. Results: We report for the first time, significant increase of serum hK6 co ncentration in a large proportion of patients with ovarian carcinoma. The e levations of hK6 appear to be relatively specific for ovarian cancer becaus e other malignancies did not cause any increase in the concentration of thi s biomarker in serum. Serial hK6 measurements appear to correlate with CA12 5 levels in patients monitored postsurgery. Conclusions: This is the first report describing significant elevations of hK6 concentration in serum of ovarian cancer patients. These data suggest t hat hK6 may represent a potential new biomarker for diagnosis and monitorin g of ovarian carcinoma. Copyright (C) 2000 The Canadian Society of Clinical Chemists.