CLDN18（claudin 18），癌症关联基因，基因ID：51208，这个基因编码克劳丁家族的一个成员claudins是完整的膜蛋白和紧密连接链的组成部分。紧密连接链是一种物理屏障，阻止溶质和水自由通过上皮细胞或内皮细胞板之间的细胞旁空间，并在维持细胞极性和信号转导方面发挥关键作用该基因在溃疡性结肠炎患者中上调，在浸润性导管腺癌中高表达PKC/MAPK/AP-1（蛋白激酶C/有丝分裂原激活蛋白激酶/激活蛋白-1）依赖性通路调控该基因在胃细胞中的表达另外，还发现了编码不同亚型的剪接转录变体。[由RefSeq提供，2010年6月]This gene encodes a member of the claudin family. Claudins are integral membrane proteins and components of tight junction strands. Tight junction strands serve as a physical barrier to prevent solutes and water from passing freely through the paracellular space between epithelial or endothelial cell sheets， and also play critical roles in maintaining cell polarity and signal transductions. This gene is upregulated in patients with ulcerative colitis and highly overexpressed in infiltrating ductal adenocarcinomas. PKC/MAPK/AP-1 (protein kinase C/mitogen-activated protein kinase/activator protein-1) dependent pathway regulates the expression of this gene in gastric cells. A。