Jahroudi N, Greenberger J S
Department of Radiation Oncology, University of Pittsburgh, PA, USA.
J Neurooncol. 1995;23(2):99-108. doi: 10.1007/BF01053415.
Metastasis is one of the most devastating aspects of cancer. It is a complex multistep processes that results in spread of tumorigenic cells to secondary sites in various organs. The actual events that are involved in metastasis are the subject of several recent reviews [1-3]. Upon growth of neoplastic cells beyond a certain mass (2 mm in diameter) an extensive vascularization through angiogenesis occurs. The new capillary network provides a supply of nutrients and gas exchange that allows further growth and development of the tumor mass. The network of the blood vessels also provides an entry site into the circulation for the neoplastic cells that detach from the tumor mass. Only a small percentage of circulating tumor cells (< 0.01%) survive travel in the circulation and arrest in the capillary beds of distant organs, extravasate and proliferate within the organ parenchyma producing a successful metastasis [1]. Vasculature plays an important role in several steps of the metastatic process; 1) at the site of metastasis, vessels capture the cancer cell and provide the entry route into the secondary organ, and 2) through angiogenesis, vascular endothelial cells provide the supply of nutrients for the growth of the primary tumor mass and the route of intravasation. The lining of all blood vessels are covered with endothelial cells which play an active role in both processes. The metastatic properties of cancer cells have been extensively studied. Here, we will discuss the role of endothelial cells in the metastatic process with focus on their interaction with cancer cells at the site of extravasation.
转移是癌症最具破坏性的方面之一。它是一个复杂的多步骤过程，导致致瘤细胞扩散到各个器官的继发部位。转移过程中涉及的实际事件是最近几篇综述的主题[1-3]。当肿瘤细胞生长超过一定大小（直径2毫米）时，通过血管生成会发生广泛的血管化。新的毛细血管网络提供营养供应和气体交换，使肿瘤块能够进一步生长和发展。血管网络还为从肿瘤块脱离的肿瘤细胞提供进入循环的入口。只有一小部分循环肿瘤细胞（<0.01%）能够在循环中存活、在远处器官的毛细血管床中滞留、渗出并在器官实质内增殖，从而形成成功的转移[1]。脉管系统在转移过程的几个步骤中起着重要作用；1）在转移部位，血管捕获癌细胞并提供进入继发器官的途径，2）通过血管生成，血管内皮细胞为原发性肿瘤块的生长提供营养供应和内渗途径。所有血管的内壁都覆盖着内皮细胞，它们在这两个过程中都发挥着积极作用。癌细胞的转移特性已经得到了广泛研究。在这里，我们将讨论内皮细胞在转移过程中的作用，重点是它们在渗出部位与癌细胞的相互作用。
