Zhan Jun, Li Xin, Yu Zhong, Yuan Yu-hong, Hou Jing
Department of Digestive Diseases, Second Affiliated Hospital of Sun Yat-sen University, Guangzhou 510120, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2007 Jul;27(7):1018-21.
To explore the value of detection of adenomatous polyposis coli (APC) gene and K-ras gene mutations in fecal and blood samples in colorectal neoplasm screening.
From 84 subjects undergoing colonoscopic examination (including 31 with colorectal carcinoma, 26 with colorectal adenoma, and 27 healthy subjects) between October, 2003 and March, 2004, 5 ml of heparinized peripheral blood and 3-5 g fecal specimens were collected. The DNA was extracted from the specimens for detecting the mutation of APC and K-ras gene using polymerase chain reaction-single strand conformation polymorphism and the results were analyzed statistically.
(1) The incidence of APC gene mutation was 41.9% and 57.7% in the plasma, and 34.8% and 26.8% in the fecal specimens of colorectal carcinoma patients and adenoma patients, respectively, both higher than that in normal subjects (P<0.05), suggesting high consistency between fecal and plasma APC gene mutation detection (K=0.811, P<0.05). (2) The incidence of plasma K-ras mutation was 48.4% in colorectal carcinoma patients, 3.8% in adenoma patients and 0% in normal control subjects, and in the feces, the incidences were 54.8%, 7.7% and 11.1%, respectively. The mutation rate was higher in carcinoma patients than in adenoma patients and normal subjects (P<0.05). Fecal K-ras gene mutation detection was consistent with plasma detection (K=0.662, P=0.000). (3) APC gene mutation detection showed a low sensitivity and specificity in the diagnosis of colorectal carcinoma, but K-ras mutation detection showed a high specificity. The diagnostic sensitivity increased when combining APC and K-ras gene detection in the plasma or fecal specimens, but there was no evidence to suggest that APC and K-ras mutation detection in the plasma could be better than detection in the feces. (4) For colorectal carcinoma, APC gene mutation is associated with lymphoid node metastasis, but not with the patient's gender, age, tumor location, differentiation, distant organ metastasis or CEA level (P>0.05), and the mutation of K-ras gene is related to the degree of tumor differentiation.
探讨粪便和血液样本中腺瘤性息肉病（APC）基因及K-ras基因突变检测在结直肠肿瘤筛查中的价值。
选取2003年10月至2004年3月间接受结肠镜检查的84例受试者（包括31例结直肠癌患者、26例结直肠腺瘤患者和27例健康受试者），采集5ml肝素抗凝外周血及3 - 5g粪便标本。从标本中提取DNA，采用聚合酶链反应-单链构象多态性方法检测APC和K-ras基因的突变情况，并进行统计学分析。
（1）结直肠癌患者血浆中APC基因突变发生率为41.9%，粪便标本中为34.8%；腺瘤患者血浆中APC基因突变发生率为57.7%，粪便标本中为26.8%，均高于正常受试者（P<0.05），提示粪便和血浆中APC基因突变检测具有较高一致性（K = 0.811，P<0.05）。（2）结直肠癌患者血浆中K-ras基因突变发生率为48.4%，腺瘤患者为3.8%，正常对照受试者为0%；粪便中K-ras基因突变发生率分别为54.8%、7.7%和11.1%。癌患者的突变率高于腺瘤患者和正常受试者（P<0.05）。粪便K-ras基因突变检测与血浆检测结果一致（K = 0.662，P = 0.000）。（3）APC基因突变检测在结直肠癌诊断中的敏感性和特异性较低，但K-ras基因突变检测具有较高的特异性。血浆或粪便标本中联合检测APC和K-ras基因时诊断敏感性增加，但无证据表明血浆中APC和K-ras基因突变检测优于粪便检测。（4）对于结直肠癌，APC基因突变与淋巴结转移相关，但与患者性别、年龄、肿瘤部位、分化程度、远处器官转移或癌胚抗原（CEA）水平无关（P>0.05），而K-ras基因突变与肿瘤分化程度有关。
