Hamostaseologie 2019; 39(S 01): S1-S92
DOI: 10.1055/s-0039-1680101
SY05 Haematology and Haemostasis
Georg Thieme Verlag KG Stuttgart · New York

Plasma Levels of Soluble CLEC-2 in Patients with Different Solid Tumors

M. Etemad
1   Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
,
J. Hassel
2   National Centre of Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
,
R. Kirsten
2   National Centre of Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
,
P. Schrotz-King
3   Division of Preventive Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
,
H. Brenner
3   Division of Preventive Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
4   Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany
,
C. Ulrich
5   Huntsman Cancer Institute and Department of Population Health Sciences, University of Utah, Salt Lake City, United States
,
P. Bugert
1   Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
13 February 2019 (online)

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    Objectives: Podoplanin is a membrane protein on the cell surface of various solid tumor types such as renal carcinoma, colon carcinoma, melanoma and mamma carcinoma. In the blood stream circulating cells of these tumors bind via podoplanin to the CLEC-2 receptor on platelets leading to tumor cell-induced platelet aggregation and thereby promoting the metastatic spread. Furthermore, it is known that soluble CLEC-2 (sCLEC-2) is shed from activated platelets but the functional role of sCLEC-2 is not known. In this study, we compared the sCLEC-2 plasma concentration of patients with tumors of the colon, skin and mamma and healthy controls.

    Methods: The study cohort included 200 patients with colon carcinoma (100 stage 1–2; 100 stage 3–4), 170 with melanoma (27 stage 1; 37 stage 2; 50 stage 3; 56 stage 4) and 103 with mamma carcinoma as well as 319 healthy blood donors. The sCLEC-2 concentrations were determined in EDTA plasma samples by using a commercial ELISA (RiaBiotech). Statistical analyses were performed in the SPSS software package.

    Results: Compared with the healthy controls cancer patients had significantly lower sCLEC-2 levels (p < 0.05): controls 1.380 ng/mL (median), colon 0.922 ng/mL, melanoma 0.717 ng/mL, mamma 0.778 ng/mL. With regard to the tumor stages of colon cancer the sCLEC-2 plasma levels were comparable. Interestingly, the melanoma stages showed a significant positive correlation with the sCLEC-2 levels (r < 0.839; p < 0.01): stage 1 0.382 ng/mL, stage 2 0.241 ng/mL, stage 3 0.638 ng/mL, stage 4 2.046 ng/mL.

    Conclusions: If circulating tumor cells significantly activate platelets one could expect higher plasma levels of sCLEC-2. However, in our study we observed lower levels of sCLEC-2 in cancer patients compared with healthy controls. We like to postulate that sCLEC-2 is bound to podoplanin-expressing cells in the blood stream and that the level of podoplanin expression is higher in cancer patients than in healthy individuals. The positive correlation of sCLEC-2 levels with melanoma stages may further indicate a balance between sCLEC-2 release from activated platelets and the level of podoplanin expression. At higher tumor stages platelet activation and sCLEC-2 release outweigh podoplanin levels. For melanoma the plasma levels of sCLEC-2 could serve as a biomarker of the tumor stage.


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    No conflict of interest has been declared by the author(s).