Gene alterations of glycosyltransferase during the course of malignant tranformation in uterine endometrium

建立了抗子宫内膜癌细胞系的单抗MSN-1，并证明它至少能识别Lewis b糖类抗原。用该抗体免疫组织化学染色，子宫内膜腺癌组织中有85%以上呈阳性反应，而正常子宫内膜组织中仅有少数呈阳性反应，提示MSN-1反应抗原可作为子宫内膜癌良好的组织化学标志物。Lewis组织血型抗原的表达由Fuct-III基因(Le基因)编码的Lewis类型α(1，3/1，4)岩藻糖基转移酶决定。由于Lewis阴性个体具有该基因错义突变(LE/LE)的等位基因纯合，从而导致酶活性失活，我们调查了子宫内膜腺癌标本中MSN-1反应抗原的表型表达是否受腺癌患者Fuct-III基因基因型的影响。为了确定Fuct-III基因的基因型，即检测突变，我们以患者外周血白细胞基因组DNA为模板，采用聚合酶链式反应-限制性片段长度多态性方法。在59例子宫内膜腺癌中，4例为Lewis阴性(LE/LE)，并用ABC免疫组织化学技术检测其癌细胞上是否存在MSN-1反应抗原。常规的血凝反应还显示，这四例患者的血型均为Lewis阴性。然而，他们的癌症组织对MSN-1呈阳性反应。这些结果表明，MSN-1识别由岩藻糖基转移酶而不是岩藻糖基转移酶构建的岩藻糖化碳水化合物。

Monoclonal antibody MSN-1 was established against an endometrial cancer cell line and proven to recognize at least Lewis b carbohydrate antigen. Immunohistochemical staining with this antibody resulted in a positive reaction in more than 85% of the endometrial adenocarcinoma cases examined but in few cases with normal endometria, indicating that MSN-1-reactive antigen is able to be a good histochemical marker for endometrial cancers. Expression of the Lewis histo-blood group antigen is determined by the Lewis type alpha (1,3/1,4) fucosyltransferase enconded by the FucT-III gene (Le gene). Since Lewis-negative individuals are known to be homozygous for an allele with missense mutations of this gene (le/le) which cause inactivation of the enzyme activity, we investigated whether or not phenotypic expression of the MSN-1-reactive antigen in endometrial adenocarcinoma specimens was affected by the genotypes of the FucT-III gene in patients with adenocarcinoma. To determine the genotypesof the FucT-III gene, i.e., to detect the mutations, we employed the polymerase chain reaction (PCR) -restriction fragment length polymorphism method by using genomic DNAs extracted from the patients'peripheral blood leucocytes as PCR templates. Out of 59 cases of endometrial adenocarcinoma, four cases with the Lewis-negative genotype (le/le) were identified and examined by the ABC immunohistochemical technique for the presence of the MSN-1-reactive antigen on their cancer cells. The conventional hemagglutination reaction also revealed all four of these cases to have the Lewis-negative blood type. However, their cancer tissues reacted positively with MSN-1. These results suggest that MSN-1 recognizes a fucosylated carbohydrate that is constructed by fucosyltransferases other than FucT-III.