Thompson J A
Institute of Immunobiology, University of Freiburg, Germany.
Tumour Biol. 1995;16(1):10-6. doi: 10.1159/000217923.
The carcinoembryonic antigen (CEA) gene family consists of approximately 30 genes, of which 17 are transcriptionally active. These genes are tightly clustered on the long arm of chromosome 19. Two main subgroups are distinguishable, one encoding CEA and its classical non-specific cross-reacting antigens (NCAs) and the second encoding the pregnancy-specific glycoproteins (PSGs). The CEA family belongs to the immunoglobulin superfamily. CEA subgroup members are either membrane bound through a glycosyl phosphatidylinositol anchor, or are integral membrane proteins, whereas PSG molecules are secreted from the cell. Despite high sequence similarity, CEA family members reveal variable expression patterns, indicating different functions. Apart from its high expression in various adenocarcinomas, CEA is found in epithelia lining the gastrointestinal tract, in eccrine sweat glands, lung epithelia and testes. The NCAs are often coexpressed with CEA, but are also found in granulocytes. PSGs are coexpressed in syncytiotrophoblast cells of the placenta, submandibular salivary glands and fetal liver, as well as in choriocarcinomas and breast tumours.
癌胚抗原（CEA）基因家族由大约30个基因组成，其中17个具有转录活性。这些基因紧密聚集在19号染色体的长臂上。可区分出两个主要亚组，一个编码CEA及其经典的非特异性交叉反应抗原（NCA），另一个编码妊娠特异性糖蛋白（PSG）。CEA家族属于免疫球蛋白超家族。CEA亚组成员要么通过糖基磷脂酰肌醇锚定与膜结合，要么是整合膜蛋白，而PSG分子则从细胞中分泌出来。尽管序列相似性很高，但CEA家族成员显示出可变的表达模式，表明其功能不同。除了在各种腺癌中高表达外，CEA还存在于胃肠道内衬上皮、外分泌汗腺、肺上皮和睾丸中。NCA通常与CEA共同表达，但也存在于粒细胞中。PSG在胎盘的合体滋养层细胞、下颌下唾液腺和胎儿肝脏中共同表达，也在绒毛膜癌和乳腺肿瘤中表达。
