目的　了解大鼠乳腺癌组织、癌旁组织和正常组织的线粒体细胞色素 b基因变异 .方法　提取细胞总 DNA,用PCR法扩增细胞色素 b基因 ,产物用 DNA自动测序法进行序列分析 .结果　癌组织发生了 nt 14931C→ G,nt 15 0 0 4C→ G和 nt 15 435 T→ C 3处点突变 .癌旁组织发生了 nt15 436A→ C突变 .正常组织没有突变 .结论　大鼠乳腺癌组织和癌旁组织线粒体细胞色素 b基因存在突变 . Objective To understand the mitochondrial cytochrome b gene mutation in rat breast cancer tissues, paracancerous tissues, and normal tissues. Methods To extract total cellular DNA and use the PCR method to amplify the cytochrome b gene. The product was sequenced using DNA sequencing. Results Cancer The nt 14931C→G, nt 15 0 0 4 C→G, and nt 15 435 T→C 3 point mutations occurred in the tissue. The nt15 436A→C mutation occurred in the adjacent tissue. There was no mutation in the normal tissue. There are mutations in the mitochondrial cytochrome b gene in adjacent tissues.