Expression of metastasis-associated Mts1 protein in human glioma

Mingqi Qu

Department of Neurosurgery

Second Affiliated Hospital of Soochow University

215004 Suzhou, China

The aim of this study was to identify the MTS1 expressing cell types in human glioma samples of different malignancy grades. MTS1 belongs to the S100 family of calcium-binding proteins, and is known to play an important role in the motility and metastatic activity of several cancer types. A differential expression of MTS1 in human glioma was found in previous studies, with a higher expression in more malignant astrocytomas. We used double immunohistochemistry to identify the cell types in human glioma as well as in normal human brain that expressed the MTS1 protein. We found that lymphocytes were the major source of MTS1 protein, and a fraction of microglia in and around blood vessels that also expressed the protein. In high-grade gliomas, a higher number of MTS1 positive cells in and around blood vessels were present compared to low-grade gliomas. Neoplastic astrocytes did not express the MTS1 protein or only at very low levels, in low-grade as well as in high-grade gliomas. Our results suggest that the reported up-regulation of MTS1 in high-grade gliomas compared to low-grade gliomas, is more likely a result of the invasion of lymphocytes and microglia that originated from peripheral blood. The MTS1 protein could be involved in this invasive movement of lymphocytes and microglia in human glioma.