28例原发性胃癌的直接染色体分析和荧光原位杂交检测

Direct chromosome analysis and FISH study of primary gastric cancer

目的 检测原发性胃癌的染色体畸变，分析这些变化在胃癌发生和发展中的作用。方法 用改良的实体瘤染色体直接制备法，对２８ 例原发性胃癌染色体进行Ｇ显带分析，在此基础上建立了一种Ｇ显带后脱色，再进行荧光原位杂交（ＦＩＳＨ） 的方法，从分子水平上证实染色体ＤＮＡ的变化。结果 病例１ ，２ 具有简单染色体数目改变，核型分别为４９，ＸＹ，＋ ２，＋ ８，＋ ９ 和４７，ＸＸ，＋ ８，＋ ２０ 。其余２６ 例原发性胃癌的染色体改变复杂，常见的染色体结构异常包括７ｑ（２１２６） 、３ｐ（１４２６） 、１ｐ（１１２６） 和１７ｐ（１０２６）。结论 原发性胃癌的染色体改变可分为两种类型：简单型只涉及１ ～３ 条染色体数目改变，８ 号和９ 号染色体三体可能构成胃癌的一个细胞遗传学亚型；复杂型涉及较多染色体数目和结构畸变，７ｑ－ 为最一致的结构异常，可认为是原发性胃癌特征性染色体结构改变之一，７ｑ３２ －

Objective To investigate chromosome aberrations and their role in the genesis and progression of primary gastric cancer.Methods An improved, direct method of chromosome preparation from solid tumors was adopted for G banding analysis followed by FISH on decolored G banding chromosomes so that chromosome aberrations could be confirmed at DNA level.Results A total of 28 primary gastric cancer specimens were studied. Case 1 and case 2 had simple chromosome numerical changes: 49, XY, +2, +8, +9 and 47, XX, +8, +20, respectively. All but case 1 and 2 had complicated chromosome abnormalities. Structural changes of frequent occurrence involved del(7q) (21/26), del(3p)(14/26), del(1p)(11/26) and del(17p)(10/26). The chromosome abnormalities could be simple or complicated. In the former, numerical changes involving 1 to 3 chromosomes could be observed. Trisomies 8 and 9 appeared to be a cytogenetic subgroup of primary gastric cancer. In the latter, del(7q) was the most consistent structural aberration. The 7q32 qter was the commonly lost segment.Conclusion Numerical and structural alterations of chromosomes are present in primary gastric cancer. Del(7q) is one of the structural changes characteristic of primary gastric cancer. In the 7q32 qter segment, a tumor suppressor gene probably exists and it may have close relation to the genesis and progression of gastric cancer.