Introduction: The prognosis of multiple myeloma is still unfavorable due to inherent characteristics of the disease and the often-delayed diagnosis due to widespread and unspecific symptoms such as back pain and fatigue. Therefore, a simple diagnostic blood test would be helpful to speed up the diagnostic procedure in such patients (pts.). Here, we evaluated the diagnostic value of plasma levels of carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) in the peripheral blood and bone marrow of pts. with plasma cell disorders and in healthy controls. Materials and Methods: Immunoreactive CEACAM6 was determined in the peripheral blood and bone marrow (n = 95/100) of pts. with monoclonal gammopathy of unknown significance (MGUS: 28/37), newly diagnosed multiple myeloma (NDMM: 42/40), and relapsed/refractory multiple myeloma (RRMM: 25/23) by sandwich ELISA. Results: Median CEACAM6 levels in the peripheral blood of pts. with plasma cell disorders were significantly higher than those of healthy controls (healthy controls: 15.2 pg/ml (12.1-17.1); MGUS: 19.0 pg/ml (16.4-22.5); NDMM: 18.0 pg/ml (13.4-21.2); and RRMM: 18.9 pg/ml (15.2-21.5); p < 0.001). Plasma levels of CEACAM6 discriminated healthy subjects from MGUS/NDMM pts. (AUC = 0.71, 95% CI: 0.6-0.8); i.e., a CEACAM6 level > 17.3 pg/ml has an 82% (95% CI: 70-90) predictive probability for the identification of MGUS or NDMM. Moreover, CEACAM6 levels in the bone marrow were significantly higher in RRMM pts. than in NDMM pts. (p = 0.04), suggesting a role of this molecule in disease progression. Conclusion: CEACAM6 plasma levels can noninvasively identify pts. with a plasma cell disorder and should be evaluated prospectively as a potential diagnostic marker. Moreover, due to high CEACAM6 levels in the bone marrow in RRMM pts., this adhesion molecule might be a therapeutic target in multiple myeloma pts.

Babak Myeloma Group Department of Pathological Physiology Faculty of Medicine Masaryk University Brno Czech Republic Department of Clinical Hematology University Hospital Brno Brno Czech Republic

Department of Internal Medicine 5 Medical University of Innsbruck Innsbruck Austria

Department of Medical Statistics Informatics and Health Economics Medical University of Innsbruck Innsbruck Austria

Faculty of Medicine University of Ostrava Ostrava Czech Republic Department of Hematooncology University Hospital Ostrava Ostrava Czech Republic

Laboratory for Tumor Biology and Angiogenesis Department of Internal Medicine 5 Medical University of Innsbruck Innsbruck Austria

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