Sneath R J, Mangham D C
Royal Orthopaedic Hospital Oncology Service, Birmingham, UK.
Mol Pathol. 1998 Aug;51(4):191-200. doi: 10.1136/mp.51.4.191.
CD44 is a transmembrane glycoprotein, the variant isoforms of which are coded for by alternative splicing, with the most prolific isoform being CD44 standard. CD44 is found in a wide variety of tissues including the central nervous system, lung, epidermis, liver, and pancreas, whereas variant isoforms of CD44 (CD44v) appear to have a much more restricted distribution. Variants of CD44 are expressed in tissues during development, including embryonic epithelia. Known functions of CD44 are cellular adhesion (aggregation and migration), hyaluronate degradation, lymphocyte activation, lymph node homing, myelopoiesis and lymphopoiesis, angiogenesis, and release of cytokines. The functions of CD44 are principally dependant on cellular adhesion in one setting or another. The role of CD44 in neoplasia is less well defined, although metastatic potential can be conferred on non-metastasising cell lines by transfection with a variant of CD44 and high levels of CD44 are associated with several types of malignant tumours. The physiological functions of CD44 indicate that the molecule could be involved in the metastatic spread of tumours. Many studies have investigated the pattern of CD44 distribution in tumours and some observations suggest that certain cells do not use CD44 in tumorigenesis or in the production of metastases. However, the data are extremely conflicting, and further studies are needed to establish the prognostic value of CD44 and its variant isoforms. The precise function of CD44 in the metastatic process and the degree of involvement in human malignancies has yet to be established fully.
CD44是一种跨膜糖蛋白，其变异体亚型由可变剪接编码，其中最常见的亚型是标准CD44。CD44存在于多种组织中，包括中枢神经系统、肺、表皮、肝脏和胰腺，而CD44的变异体亚型（CD44v）的分布似乎更为局限。CD44的变异体在发育过程中的组织中表达，包括胚胎上皮。CD44的已知功能包括细胞黏附（聚集和迁移）、透明质酸降解、淋巴细胞活化、淋巴结归巢、髓系造血和淋巴细胞生成、血管生成以及细胞因子释放。CD44的功能主要取决于在某种情况下的细胞黏附。CD44在肿瘤形成中的作用尚不清楚，尽管通过转染CD44变异体可赋予非转移细胞系转移潜能，且高水平的CD44与几种类型的恶性肿瘤相关。CD44的生理功能表明该分子可能参与肿瘤的转移扩散。许多研究调查了CD44在肿瘤中的分布模式，一些观察结果表明某些细胞在肿瘤发生或转移产生过程中不使用CD44。然而，数据极为矛盾，需要进一步研究以确定CD44及其变异体亚型的预后价值。CD44在转移过程中的精确功能以及在人类恶性肿瘤中的参与程度尚未完全明确。
