Watanabe H, Yamaguchi Y, Ha A, Hu Y X, Motoo Y, Okai T, Yoshimura T, Sawabu N
Department of Internal Medicine and Medical Oncology, Kanazawa University, Japan.
Pancreas. 1998 Nov;17(4):341-7. doi: 10.1097/00006676-199811000-00004.
K-ras mutations at codon 12 (KRM) have been detected in approximately 80% of samples of pure pancreatic juice (PPJ) from patients with pancreatic cancer (PCa) and are a promising potential tumor marker. However, the frequent presence of KRM was reported in PPJ from noncancerous patients as determined by a highly sensitive method, raising questions as to the cancer specificity of this marker. Therefore we evaluated whether the hybridization protection assay (HPA), which can quantitatively determine KRM in PPJ, is useful for the diagnosis of PCa, differentiating from chronic pancreatitis (CP). PPJ was collected endoscopically from 29 patients with PCa, 26 patients with CP, and the 11 cases as the control group. Polymerase chain reaction (PCR) and HPA using an acridinium ester-labeled DNA probe for KRM were performed with DNA extracted from these samples. The results were compared with those obtained by PCR-restriction fragment length polymorphism (RFLP). The mean + 2 SD of chemiluminescence in the control group was 11,020 RLUs. When 11,020 RLUs was taken as the cut-off value, KRM was detected by PCR-HPA in 19 (66%) of 29 of PCa and one (4%) of 26 of CP cases. Analysis of PPJ by PCR-RFLP demonstrated KRM in 22 (79%) of 28 of PCa and five (19%) of 26 of CP cases. However, four of five patients with CP who were KRM-positive by PCR-RFLP were defined as negative by PCR-HPA, suggesting that PCR-HPA is superior to PCR-RFLP for the discrimination between PCa and CP. These findings indicate that quantitative analysis of KRM in PPJ using the PCR-HPA method is a promising approach for the diagnosis of PCa, differentiating from CP with a suitable cut-off value, as in the case with the use of conventional serum tumor marker.
在胰腺癌（PCa）患者的约80%纯胰液（PPJ）样本中检测到第12密码子的K-ras突变（KRM），其是一种很有前景的潜在肿瘤标志物。然而，通过一种高灵敏度方法测定发现，非癌患者的PPJ中也频繁存在KRM，这引发了对该标志物癌症特异性的质疑。因此，我们评估了可定量测定PPJ中KRM的杂交保护分析（HPA）对于PCa诊断（与慢性胰腺炎（CP）相鉴别）是否有用。通过内镜从29例PCa患者、26例CP患者以及11例作为对照组的患者中收集PPJ。使用针对KRM的吖啶酯标记DNA探针，对从这些样本中提取的DNA进行聚合酶链反应（PCR）和HPA。将结果与通过PCR-限制性片段长度多态性（RFLP）获得的结果进行比较。对照组化学发光的平均值 + 2标准差为11,020相对光单位（RLU）。以11,020 RLU作为临界值时，通过PCR-HPA在29例PCa中的19例（66%）以及26例CP中的1例（4%）检测到KRM。通过PCR-RFLP分析PPJ显示，28例PCa中的22例（79%）以及26例CP中的5例（19%）存在KRM。然而，PCR-RFLP检测为KRM阳性的5例CP患者中有4例被PCR-HPA判定为阴性，这表明在区分PCa和CP方面，PCR-HPA优于PCR-RFLP。这些发现表明，如同使用传统血清肿瘤标志物一样，采用PCR-HPA方法对PPJ中的KRM进行定量分析是一种有前景的PCa诊断方法，通过合适的临界值可与CP相鉴别。
