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在肿瘤发生发展过程中往往伴有癌基因和抗癌基因的突变,这有可能成为特异的肿瘤标记。由于结直肠肿瘤细胞可向肠腔内脱落,如能从粪便中检出瘤细胞内突变的癌基因,则可为结直肠癌的早期发现提供一个新的检测手段。作者首先从24例结直肠肿瘤的冰冻切片中提取DNA,经聚合酶链式反应(PCR)扩增后,对PCR产物进行克隆、测序,发现有9例(37％)在K-ras癌基因的第一个外显子上,第12或13编码子有突变(Gly~(12)→Val~(12),Gly~(12)→Asp~(12),或Gly~(13)→Asp~(13))。突变出现的频率与以往报道一致。
In the process of tumor development, it is often accompanied by mutations in oncogenes and anti-oncogenes, which may become specific tumor markers. As colorectal tumor cells can fall off into the lumen of the intestine, detection of mutated oncogenes in tumor cells from the feces can provide a new detection method for the early detection of colorectal cancer. The authors first extracted DNA from frozen sections of 24 colorectal tumors and amplified them by polymerase chain reaction (PCR). The PCR products were cloned and sequenced and 9 cases (37%) were found to have K-ras oncogenes. On the first exon, there is a mutation in the 12th or 13th codon (Gly~(12)→Val~(12), Gly~(12)→Asp~(12), or Gly~(13)→Asp ~(13)). The frequency of mutations is consistent with previous reports.