中文摘要：

叶酸受体（FR）在许多上皮源性和非上皮源性恶性肿瘤细胞显著高表达，其表达水平大大高于正常细胞，具有组织特异性。FR是细胞摄取叶酸的重要途径，其机制为受体介导的内吞效应，这种机制具有亲和力高、特异性强的特点，有良好的物质转运应用潜能。大量研究结果显示，连接叶酸分子的核素、荧光素以及磁共振成像（MRI）对比剂等靶向诊断试剂通过与FR特异结合，能够检测出阳性表达FR的肿瘤组织，而正常组织无此效应，提示FR靶向的肿瘤诊断策略的可行性和应用前景。

英文摘要：

Folate receptors （FR） are up-regulated in a variety of epithelium-derived and non epithelium- derived human cancers, and the expression is greatly higher than that in normal cells and has tissue specific- ity. FR is an important way for cells＇ uptake of folate. Its mechanism is endocytosis mediated by receptors, and this mechanism has high affinity, high specificity and good potential to transport substances. Many studies show that FR-expressing cancer tissues can be detected by combining specifically targeted diagnosis agents such as radionuclide linked with folate,fluorescein and MRI contrast agents with FR, there is no such effect in normal tissues. This indicates the feasibility and application prospect of FR-targeted tumor diagnosis strategies.