Kieran M W, Longenecker B M
Cancer Metastasis Rev. 1983;2(2):165-82. doi: 10.1007/BF00048968.
Many malignant tumors demonstrate a definite propensity for metastasis to specific organs despite the fact that tumor cells with the potential for metastasis may circulate randomly throughout the body. Current concepts of organ specific metastasis (OSM) center around the generation of tumor cell variants with enhanced capacity for metastasis to specific organs. At present three hypotheses, mechanical, seed and soil, and specific tumor cell adherence (STCA), stand out as possible explanations for OSM. These possible mechanisms of OSM are by no means mutually exclusive. Recent efforts to understand OSM have included the selection of organ-specific metastasizing variants from tumor cell lines and an examination of their surface and metastatic properties. OSM-selected cell lines from many different tumor systems have been used to examine the relative contributions of the three mechanisms. While examples of each mechanism have been reported, the relative contributions of each for different tumor systems may differ substantially. Therefore, generalizations about the behavior of tumors based on studies with just a few tumor lines and systems may not be valid. There is substantial evidence that cell surface molecules are important in the process of OSM and homing of lymphocytes to specific lymph nodes. Monoclonal antibodies have been produced against putative cell surface receptors and initial biochemical characterization has begun. There is much evidence that cell surface glycoconjugates can serve as specific recognition structures on normal cells and in addition, may play important roles in OSM. The role of these carbohydrates is discussed. The chick embryo as a model system is discussed as it offers several advantages for the study of metastasis in general and OSM in particular. A variety of human and murine tumors, including some freshly isolated, have been shown to grow and metastasize in these embryos. Furthermore, cell lines which have been selected for OSM in adults show similar patterns of metastasis in chick embryos indicating that this system may be an especially attractive one for the analysis of OSM.
尽管具有转移潜能的肿瘤细胞可能随机循环至全身，但许多恶性肿瘤表现出向特定器官转移的明确倾向。目前关于器官特异性转移（OSM）的概念围绕着具有增强的向特定器官转移能力的肿瘤细胞变体的产生。目前，机械学说、种子与土壤学说以及特异性肿瘤细胞黏附（STCA）学说这三种假说，作为OSM的可能解释脱颖而出。这些OSM的可能机制绝非相互排斥。近期为理解OSM所做的努力包括从肿瘤细胞系中选择器官特异性转移变体，并研究其表面和转移特性。来自许多不同肿瘤系统的经OSM选择的细胞系已被用于研究这三种机制的相对作用。虽然每种机制的例子都有报道，但每种机制对不同肿瘤系统的相对作用可能有很大差异。因此，仅基于少数肿瘤系和系统的研究对肿瘤行为进行概括可能并不有效。有大量证据表明细胞表面分子在OSM过程以及淋巴细胞归巢至特定淋巴结中起重要作用。已经制备了针对假定细胞表面受体的单克隆抗体，并且已经开始进行初步的生化表征。有许多证据表明细胞表面糖缀合物可作为正常细胞上的特异性识别结构，此外，可能在OSM中发挥重要作用。本文讨论了这些碳水化合物的作用。本文讨论了将鸡胚作为模型系统，因为它为一般的转移研究，特别是OSM研究提供了几个优势。包括一些新鲜分离的肿瘤在内，多种人类和小鼠肿瘤已被证明能在这些胚胎中生长和转移。此外，在成体中经OSM选择的细胞系在鸡胚中表现出相似的转移模式，这表明该系统对于分析OSM可能特别有吸引力。
