PCDH9（protocadherin 9），癌症关联基因，基因ID：5101，该基因编码含有钙粘蛋白结构域的跨膜蛋白原钙粘蛋白家族成员和钙粘蛋白超家族这些蛋白质在钙的存在下介导神经组织中的细胞粘附。编码蛋白可能参与神经元突触连接处的信号传导。与其他原钙粘蛋白基因一样，该基因有一个显著的大外显子，编码多个钙粘蛋白结构域和跨膜区。另外，已经发现该基因编码不同亚型的剪接转录变体[由RefSeq提供，2012年11月]This gene encodes a member of the protocadherin family， and cadherin superfamily， of transmembrane proteins containing cadherin domains. These proteins mediate cell adhesion in neural tissues in the presence of calcium. The encoded protein may be involved in signaling at neuronal synaptic junctions. Sharing a characteristic with other protocadherin genes， this gene has a notably large exon that encodes multiple cadherin domains and a transmembrane region. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq， Nov 2012]。