David L, Leitao D, Sobrinho-Simoes M, Bennett E P, White T, Mandel U, Dabelsteen E, Clausen H
Unit of Molecular Pathology Faculty of Medicine, University of Porto, Portugal.
Cancer Res. 1993 Nov 15;53(22):5494-500.
The expression of incompatible A carbohydrate antigens in some adenocarcinomas may provide an explanation for the generally observed lower incidence of adenocarcinoma among types O and B versus type A individuals. The chemistry and genetic basis of incompatible A expression is largely unknown. Here, we have screened 31 cases of gastric tumors of phenotype O for the expression of blood group A gene-defined glycosyltransferase by immunohistology on frozen sections using newly developed monoclonal antibodies to the transferases. Three cases were positive, and transferase expression was confirmed by enzyme analysis of extracts from the specimens. Blood group A carbohydrate antigens were also identified immunohistologically in these three cases as well as in five other cases. Thin-layer chromatography immunostaining analysis of glycolipid extracts from the three cases did not confirm the chemical presence of A antigen. The ABO genotype of all patients was found to be OO, showing that all carried O alleles with a structural defect at nucleotide position 261 leading to a shift in the reading frame. The data suggest that incompatible A antigen expression is a result of transferase expression derived from the ABO genes.
某些腺癌中不相容A碳水化合物抗原的表达，可能为O型和B型个体相对于A型个体中普遍观察到的腺癌发病率较低提供一种解释。不相容A表达的化学和遗传基础在很大程度上尚不清楚。在此，我们使用新开发的针对转移酶的单克隆抗体，通过对冰冻切片进行免疫组织学检查，筛选了31例O型表型的胃肿瘤，以检测血型A基因定义的糖基转移酶的表达。3例呈阳性，通过对标本提取物的酶分析证实了转移酶的表达。在这3例以及其他5例中，也通过免疫组织学鉴定出了血型A碳水化合物抗原。对这3例的糖脂提取物进行的薄层色谱免疫染色分析未证实A抗原的化学存在。发现所有患者的ABO基因型均为OO，表明所有患者都携带O等位基因，其在核苷酸位置261处存在结构缺陷，导致阅读框移位。数据表明，不相容A抗原的表达是ABO基因衍生的转移酶表达的结果。
