Wang Ying, Yamaguchi Yasushi, Watanabe Hiroyuki, Ohtsubo Koushirou, Motoo Yoshiharu, Sawabu Norio
Department of Internal Medicine and Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.
Pancreas. 2004 Jan;28(1):13-9. doi: 10.1097/00006676-200401000-00002.
The sensitivity of pure pancreatic juice (PPJ) cytology for the diagnosis of pancreatic carcinoma (PCa) is still low. The usefulness of genetic analyses of PPJ seems to be limited because of insufficient sensitivity or false positivity. To improve the molecular diagnosis of PCa, we analyzed mutations of p53 together with K-ras in DNA extracted not only from the sediment but also from the supernatant of PPJ samples.
Polymerase chain reaction-single-strand conformation polymorphism and direct sequencing were used for analyses of p53 mutations in exons 5-8. K-ras mutations at codon 12 were examined by mutant allele-specific amplification.
In PPJ supernatant from patients with PCa, p53 and K-ras mutations were detected in 42.9% (9 of 21) and 81.0% (17 of 21) of cases, respectively. The incidence of p53 and K-ras mutations in the sediment was 28.6% and 71.4%, respectively. By a combination assay with supernatant and sediment, p53 mutations were detected in 52.4% (11 of 21) of PCa cases. Moreover, p53 mutations were detected in 7 of 15 (46.7%) cases of PCa in which the cytologic diagnosis was negative. Among 25 patients with chronic pancreatitis (CP), none harbored mutant p53, although K-ras mutations were detected at an incidence of 28% (7 of 25) in the supernatant and 20% (5 of 25) in the sediment. In addition, mutant bands of p53 in plasma were detected in 2 of 11 patients with PCa in whom p53 mutations were detectable in PPJ.
These results suggest that the sensitivity of detection for p53 mutations with high cancer specificity could be improved by using the Sup in PPJ samples of PCa. Genetic analysis of p53 could complement PPJ cytology. p53 mutations were detectable in PCa from plasma samples.
纯胰液（PPJ）细胞学诊断胰腺癌（PCa）的敏感性仍然较低。由于敏感性不足或假阳性，PPJ的基因分析的实用性似乎有限。为了改善PCa的分子诊断，我们不仅分析了PPJ样本沉淀物中的DNA，还分析了上清液中的DNA中p53和K-ras的突变情况。
采用聚合酶链反应-单链构象多态性分析和直接测序法分析外显子5-8中p53的突变情况。通过突变等位基因特异性扩增检测密码子12处的K-ras突变。
在PCa患者的PPJ上清液中，分别在42.9%（21例中的9例）和81.0%（21例中的17例）的病例中检测到p53和K-ras突变。沉淀物中p53和K-ras突变的发生率分别为28.6%和71.4%。通过上清液和沉淀物联合检测，在52.4%（21例中的11例）的PCa病例中检测到p53突变。此外，在15例细胞学诊断为阴性的PCa病例中，有7例（46.7%）检测到p53突变。在25例慢性胰腺炎（CP）患者中，均未检测到p53突变，但在上清液中K-ras突变的发生率为28%（25例中的7例），在沉淀物中为20%（25例中的5例）。此外，在11例PPJ中可检测到p53突变的PCa患者中，有2例在血浆中检测到p53突变条带。
这些结果表明，通过使用PCa的PPJ样本中的上清液，可以提高对具有高癌症特异性的p53突变的检测敏感性。p53的基因分析可以补充PPJ细胞学检查。在血浆样本中可检测到PCa中的p53突变。
