胃癌细胞系和胃癌组织中线粒体DNA4 977 bp缺失及其生物学意义

目的 明确线粒体DNA 4977bp大片段缺失在胃癌细胞系、胃癌组织及胃癌患者血清中的频率,为胃癌的早期临床诊断寻找简便准确的分子标记。方法 运用Primer-shift PCR和直接测序的方法对13个胃癌细胞系、52对胃癌组织及对应的癌旁正常组织（年龄从28-78岁）、40例胃癌患者血清及40名正常人血清进行筛查。取10例胃癌组织的石蜡切片,采用显微切割技术在同一患者的切片上同时分离3种组织（包括胃粘膜正常腺体、肠化上皮及胃癌组织）对mtDNA 4977bp缺失进行了分析比较。结果 在13个胃癌细胞系中12个有mtDNA4977bp缺失（缺失率为92.3%),52例胃癌组织中38例有缺失（缺失率为73.1%),52例癌旁正常组织中27例有缺失（缺失率为52%）,40名胃癌患者血清中17例有缺失（缺失率为42.5%),40名正常人血清中8例有缺失（缺失率为20%）。胃癌组织和癌旁正常组织mtDNA 4977bp缺失差异有显著意义,癌组织mtDNA 4977bp缺失率与胃癌的分型和患者的性别没有关联。胃癌患者血清与正常人血清mtDNA4977bp缺失差异也有显著意义。10例显微切割组织中2例肠化上皮及胃癌组织中有缺失,而胃粘膜正常腺体未见缺失。结论 线粒体DNA 4977bp大片段缺失可能在胃癌发生和胃粘膜病变演化及细胞癌变的过程中起重要作用,血清中可以检测到线粒体DNA 4977bp大片段缺失,而且在胃癌患者血清中检出率远高于正常人血清。检测胃癌患者血清中mtDNA 4977bp大片段缺失有望成为一种简便易行的胃癌生物学行为的分子标记物。

Frequent 4 977 bp deletion of mitochondrial DNA in tumor cell lines, solid tumors and precancerous lesions of human stomach

OBJECTIVE: To clarify the frequency of mtDNA 4 977 bp deletion in tumor cell lines, solid tumors, patient's serum of gastric tumor and to find a easy and exact method to diagnose gastric tumor. METHODS: Primer-shift PCR method was used in 13 gastric tumor cell lines, 52 cases of gastric fresh tumor tissues matched the adjacent normal tissues, 40 cases of patient's serum of gastric tumor and 40 cases of normal serums for analysis of mtDNA deletion. RESULTS: Frequency of 4 977 bp mtDNA deletion was detected in 12 of 13 (92.3%) tumor cell lines, 38 of 52 (73.1%) cases of solid tumor tissues, 27 of 52 (52%) adjacent normal tissues, 17 of 40 (42.5%) patient's serum and 8 of 40 (20%) normal serums. Further more, in 2 of 10 pairs microdissected specimens, we found this deletion occurred not only in primary tumor but also in intestinal metaplasia comparing with no deletion was found in normal tissues. The frequency of this deletion was statistically significantly higher in the gastric tumor tissues and serums than in the adjacent normal tissues and serums. A good correlation between the deletion and young age of patients was representative in our data. CONCLUSION: mtDNA 4 977 bp deletion maybe play an important role in the carcinogenesis of human gastric mucous and maybe has happened in the tumor cell malignant transformation. To detect this deletion in patient's serum is a easy and exact method and maybe become a potential tumor marker.