Meldgaard P, Johnson P H, Langkilde N C, Wolf H, Orntoft T F
Department of Urology, Aarhus University Hospital, Denmark.
Int J Cancer. 1995 Nov 3;63(3):341-4. doi: 10.1002/ijc.2910630306.
The significance of loss of heterozygosity (LOH) of chromosome 9 as an early event in human bladder tumors has been demonstrated by several studies. We have studied LOH of the ABO gene locus at 9q34.2 by means of polymerase chain reaction (PCR) genotyping of tumor preparations and leukocytes. Twenty-two tumors, all of which were immunohistochemically negative for ABH antigens, were examined. Eleven tumors were from blood-group O individuals, and were examined by denaturing gradient gel electrophoresis (DGGE). They showed normal band patterns with no sign of single base mutations or LOH. All II A and B tumors were sorted on a fluorescence-activated cell sorter (FACS) according to DNA content, thereby making it possible to study differences in genotype between subpopulations of cells in the same tumor. In 2 genotypically AO cases, we found 2 aneuploid subpopulations. In both cases, the most abnormal, with the highest DNA content, showed complete loss of the O allele, leaving the A allele intact. As all tumors were ABH antigen-negative, this study demonstrates that LOH of the ABO locus on chromosome 9q34 is not the cause of loss of blood-group ABH expression in human bladder cancer.
几项研究已证明9号染色体杂合性缺失（LOH）作为人类膀胱肿瘤早期事件的重要性。我们通过对肿瘤标本和白细胞进行聚合酶链反应（PCR）基因分型，研究了位于9q34.2的ABO基因座的LOH。对22例肿瘤进行了检查，所有肿瘤ABH抗原免疫组化均为阴性。11例肿瘤来自O血型个体，通过变性梯度凝胶电泳（DGGE）进行检查。它们显示出正常的条带模式，没有单碱基突变或LOH的迹象。所有II A型和B型肿瘤均根据DNA含量在荧光激活细胞分选仪（FACS）上进行分选，从而能够研究同一肿瘤细胞亚群之间的基因型差异。在2例基因型为AO的病例中，我们发现了2个非整倍体亚群。在这两个病例中，最异常的、DNA含量最高的亚群显示O等位基因完全缺失，而A等位基因保持完整。由于所有肿瘤ABH抗原均为阴性，本研究表明9q34上ABO基因座的LOH不是人类膀胱癌中血型ABH表达缺失的原因。
