title: Differential changes in platelet VEGF, Tsp, CXCL12, and CXCL4 in patients with metastatic cancer.
abstract: Data from animal studies indicate that platelets play a key role in tumor dissemination and metastasis. We therefore hypothesized that metastastic cancer patients may display a specific platelet phenotype. Percentage of activated, p-selectin positive platelets as well as platelet contents (i.e., plasma and platelet count-corrected serum levels of VEGF-A, CXCL12, CXCL4, and thrombospondin-1) were analyzed in 43 patients with newly diagnosed metastatic disease prior to treatment. Tumor patients had increased platelet counts and significantly elevated percentages of activated platelets. Moreover, the platelet content of VEGF-A in cancer patients was significantly increased compared to healthy controls, while thrombospondin-1, CXCL12 and CXCL4 were significantly decreased. Our data contain several unexpected results: firstly, CXCL12 was found in minute quantities in the serum as compared with murine studies. Secondly, CXCL4, which was found by mass spectrometry to be the single massively upregulated intraplatelet chemokine in mice after tumor xenotransplantation, was decreased in tumor patient platelets. While increased contents of VEGF-A have been attributed to platelet scavenger activity, the differential decrease of specific platelet contents may be due to differential secretion or altered megakaryopoiesis in metastatic cancer patients.
authors.affiliation: Department of Hematology/Oncology, Eberhard Karls-University, Otfried-Mueller-Str. 10, Tuebingen, Germany.
authors.forename: Tina
authors.initials: T
authors.lastname: Wiesner
authors.forename: Stefanie
authors.initials: S
authors.lastname: Bugl
authors.forename: Frank
authors.initials: F
authors.lastname: Mayer
authors.forename: Jörg T
authors.initials: JT
authors.lastname: Hartmann
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Kopp
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis; D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D054377:Chemokine CXCL12 / Q000097:blood* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D013058:Mass Spectrometry; D008533:Megakaryocytes / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009362:Neoplasm Metastasis / Q000473:pathology*; D009367:Neoplasm Staging; D010976:Platelet Count; D010978:Platelet Factor 4 / Q000097:blood* / Q000378:metabolism; D019700:Thrombospondin 1 / Q000097:blood* / Q000378:metabolism; D042442:Vascular Endothelial Growth Factors / Q000097:blood* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D054377:Chemokine CXCL12; D019700:Thrombospondin 1; D042442:Vascular Endothelial Growth Factors; D010978:Platelet Factor 4