Thrombospondin Levels in Patients with Malignancy

Abstract

SummaryThrombospondin (TSP), a large glycoprotein present in platelets, and various normal and tumor tissues, has recently been shown to promote cell adhesion and platelet aggregation. Most importantly because TSP has been shown to promote metastasis of melanoma tumor cells to the lung in a murine model (1) and since thromboembolic events commonly occur in patients afflicted with metastatic tumors, we explored the role of TSP in human cancer by measuring TSP blood levels in patients with various malignant neoplasms. Blood TSP levels were measured by indirect enzyme-linked immunoadsorbent assay (ELISA) from 20 control subjects, 22 patients with gastrointestinal (GI) cancer, 18 patients with breast cancer, and 17 patients with lung cancer. Control subjects consisted both of healthy subjects and acutely ill patients with no malignancies. TSP levels of both healthy and acutely ill controls were found to range between 245-440 μg/ml with a mean of 365 μg/ml. In contrast, elevated levels of TSP greater than the mean value of 400 μg/ml for controls ranging between 590-3,650 μg/ml were found in 20/22 (91%) patients with GI malignancies, 13/18 (72%) patients with breast cancer, and 15/17 (88%) with lung cancer. Mean TSP levels of GI, breast, and lung cancer patients were 3, 2, and 3 fold greater than controls, respectively. Increased blood TSP levels in patients were not due to increased levels of platelets since both control and patient groups had platelet counts within the normal range. These results suggest that TSP may play a role in tumor cell metastasis in man and could serve as a blood marker for metastasis.

Development of Glycoprotein Capture-Based Label-Free Method for the High-throughput Screening of Differential Glycoproteins in Hepatocellular Carcinoma

“…TSP-1 that is present in the tumor microenvironment also acts to suppress tumor cell growth through activation of transforming growth factor ␤ in those tumor cells that are responsive to TGF-␤ (55). TSP-1 has been shown to be highly expressed in human malignant tissues and present in higher than normal levels in the plasma of cancer patients (56), like beast, lung, and colorectal carcinoma (57), which is in contrast with our result, suggesting a possible unique figure of hepatocellular carcinoma.…”

Expression of angiogenic markers in the peripheral blood of docetaxel-treated advanced breast cancer patients: A Hellenic Cooperative Oncology Group (HeCOG) study

“…Ductal cancers express THBS-1 mainly in the surrounding stroma, while in lobular tumors it is present in the more invasive tumor cells (33). In accordance with these observations, Tuszynski et al and Byrne et al found higher blood levels of THBS-1 protein in breast cancer patients compared to healthy controls (34,35), while the present study showed that blood THBS-1 mRNA levels are also elevated. Thrombospondins are secreted in blood by platelets and monocytes (36).…”

Plasma thrombospondin levels in patients with colorectal carcinoma

“…A correlation between the plasma thrombosponies 38 and antithrombospondin antibodies 39 have been shown to prevent the development of metastasis in din levels and the stage of colorectal carcinoma was observed. Because the plasma thrombospondin level the murine model.…”