Carvalho B, Seruca R, Carneiro F, Buys C H, Kok K
Instituto de Patologia e Imunologia da Universidade do Porto, IPATIMUP, Porto, Portugal.
Genes Chromosomes Cancer. 1999 Sep;26(1):29-34.
Deletions of the long arm of chromosome 6 are a common event in gastric carcinomas. In a previous study, deletion mapping of 6q identified two smallest regions of overlap (SROs) of heterozygous deletions: one interstitial, spanning 12-16 cM, bordered by D6S268 (6q16.3-q21) and ARG1 (6q22.3-q23.1), and one distal to IFNGR1 (6q23-q24), spanning more than 30 cM. Loss of heterozygosity (LOH) of the interstitial SRO was detected in 50% of informative tumors. We analyzed 60 primary gastric tumors with 19 highly polymorphic markers from 6q16.3-q23.3 to delimit the interstitial SRO further. Of the 50 tumors that were informative for at least one locus, 18 (36%) showed allelic imbalance (AI). The overlap of these cases allowed us to define an SRO of approximately 3 Mb flanked by D6S278 and D6S404. AI or LOH of this region occurs in all histologic types of gastric carcinoma and in early stages of development, indicating that loss of a gene from this region of 6q is a crucial step in a main route of gastric carcinogenesis. For cases with retention of 6q, alternative routes of gastric carcinogenesis may exist. Genes Chromosomes Cancer 26:29-34, 1999.
6号染色体长臂缺失在胃癌中是常见事件。在先前的一项研究中，对6q进行缺失图谱分析确定了杂合性缺失的两个最小重叠区域（SRO）：一个位于间质，跨度为12 - 16 cM，边界为D6S268（6q16.3 - q21）和ARG1（6q22.3 - q23.1），另一个位于IFNGR1（6q23 - q24）远端，跨度超过30 cM。在50%的信息丰富的肿瘤中检测到间质SRO的杂合性缺失（LOH）。我们用来自6q16.3 - q23.3的19个高度多态性标记分析了60例原发性胃癌，以进一步界定间质SRO。在至少一个位点信息丰富的50例肿瘤中，18例（36%）显示出等位基因不平衡（AI）。这些病例的重叠区域使我们能够确定一个约3 Mb的SRO，其两侧为D6S278和D6S404。该区域的AI或LOH出现在所有组织学类型的胃癌以及早期发育阶段，表明6q这个区域的一个基因缺失是胃癌发生主要途径中的关键步骤。对于保留6q的病例，可能存在胃癌发生的替代途径。《基因、染色体与癌症》26:29 - 34，1999年。
