Burgart L J, Zheng J, Shu Q, Strickler J G, Shibata D
Department of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota, USA.
Am J Pathol. 1995 Oct;147(4):1105-11.
Likely hot spots for mutations are mitochondrial sequences as there is less repair and more damage by carcinogens compared with nuclear sequences. A somatic 50-bp mitochondrial D-loop deletion was detected in four gastric adenocarcinomas. The deletion included the CSB2 region and was flanked by 9-bp direct repeats. The deletion was more frequent in adenocarcinomas arising from the gastroesophageal junction (4/32, 12.5%) compared with more distal tumors (0/45). Topographical analysis revealed the absence of the deletion from normal tissues except in focal portions of smooth muscle in one case. In two cases, apparent mutant homoplasmy was present throughout two tumors, including their metastases. In the two other cases, the mutation was present in only minor focal portions ( < 5%) of their primary tumors. These findings document the presence of somatic mitochondrial alterations in gastric cancer, which may reflect the environmental and genetic influences operative during tumor progression.
与核序列相比，线粒体序列可能是突变的热点区域，因为其修复能力较弱且致癌物造成的损伤更多。在4例胃腺癌中检测到了一个50bp的体细胞线粒体D环缺失。该缺失包括CSB2区域，两侧为9bp的直接重复序列。与更远端的肿瘤（0/45）相比，胃食管交界部产生的腺癌中该缺失更为常见（4/32，12.5%）。拓扑分析显示，除了1例平滑肌局部区域外，正常组织中不存在该缺失。在2例病例中，两个肿瘤及其转移灶中均呈现明显的突变纯质性。在另外2例病例中，该突变仅存在于原发肿瘤的微小局部区域（<5%）。这些发现证明了胃癌中存在体细胞线粒体改变，这可能反映了肿瘤进展过程中起作用的环境和遗传影响。
