Abstract
We investigated the distribution and formation of new lymphatic vessels in gliomas. Specimens from seven glioma cases were analyzed by immunohistochemical staining for CD34, lymphatic endothelial hyaluronic acid receptor 1 (LYVE-1), prospero-related homeobox 1 (Prox1), nestin, and hypoxia-inducible factor 1α (HIF-1α). Three types of vessels were observed in glioma specimens: LYVE-1(+) lymphatic vessels, CD34(+) blood vessels, and LYVE-1(+) /CD34(+) blood vessels. Prox1(+) /LYVE-1(+) cells were distributed in some lymphatic vessels as well as among vascular endothelial cells and glioma cells. Nestin(+) cells were scattered throughout the gliomas, and some lymphatic cells also expressed nestin. HIF-1α(+) Prox1(+) cells were widely distributed within the glioma specimens. The present immunohistochemical analysis revealed upregulation of Prox1 and HIF-1α in some glioma tissues as well as the differentiation of nestin(+) tumor stem cells into LYVE-1(+) lymphatic vessels.