Imai M, Hoshi T, Ogawa K
Department of Pathology, Asahikawa Medical College, Japan.
Cancer. 1994 Jun 1;73(11):2727-33. doi: 10.1002/1097-0142(19940601)73:11<2727::aid-cncr2820731113>3.0.co;2-#.
Although the prevalence of K-ras codon 12 mutations in biliary tract (BT) tumors has been addressed in previous studies, the results have shown large discrepancies in mutation frequency.
K-ras codon 12 mutations were investigated by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE), a sensitive method for detecting DNA base changes, in a large series of BT tumors.
In A-549 cells, which are known to contain a G to A change at the first base of K-ras codon 12, the mutation could be detected by DGGE even after 1:16 dilution with normal DNA. Tumor samples were microdissected from paraffin embedded tissue sections to ensure the presence of the tumor cells. K-ras mutations were detected in 13 of 23 bile duct tumors (56.5%) and in 9 of 23 gallbladder tumors (39.1%) by DGGE. However, no mutations were detected in normal, hyperplastic, and dysplastic BT epithelium or in tumorlike lesions, such as adenomyomatous hyperplasia, cholesterol polyps, and cystitis glandularis proliferans. The samples exhibiting abnormalities on DGGE showed a base change at K-ras codon 12 when examined by oligonucleotide hybridization.
K-ras codon 12 mutations are seen often in BT tumors, and a combination of microdissection and PCR-DGGE is an effective approach for their detection.
尽管先前的研究已探讨过胆道（BT）肿瘤中K-ras密码子12突变的发生率，但结果显示突变频率存在很大差异。
采用聚合酶链反应（PCR）-变性梯度凝胶电泳（DGGE）（一种检测DNA碱基变化的灵敏方法）对大量BT肿瘤进行K-ras密码子12突变检测。
在已知K-ras密码子12第一个碱基存在G到A变化的A-549细胞中，即使与正常DNA按1:16稀释后，DGGE仍能检测到该突变。从石蜡包埋组织切片中显微切割肿瘤样本以确保肿瘤细胞的存在。通过DGGE在23例胆管肿瘤中的13例（56.5%）和23例胆囊肿瘤中的9例（39.1%）检测到K-ras突变。然而，在正常、增生和发育异常的BT上皮或肿瘤样病变（如腺肌瘤样增生、胆固醇息肉和增殖性腺性膀胱炎）中未检测到突变。在DGGE上显示异常的样本经寡核苷酸杂交检测时，在K-ras密码子12处出现碱基变化。
K-ras密码子12突变在BT肿瘤中常见，显微切割和PCR-DGGE联合是检测这些突变的有效方法。
