Telomerase activity in pure pancreatic juice for the diagnosis of pancreatic cancer may be complementary to K-ras mutation

Background: The usefulness of K-ras mutation in pancreatic juice for the diagnosis of pancreatic cancer is questionable. Telomerase is positive in pancreatic cancer but rarely in benign pancreatic diseases. We conducted this study to determine the usefulness of K-ras mutation and telomerase activity in pancreatic juice for the diagnosis of pancreatic cancer. Methods: Pancreatic juice collected during endoscopic retrograde cholangiopancreatography was examined in 31 patients: 12 with pancreatic cancer, 11 with chronic pancreatitis, and 8 control patients. The K-ras gene was detected by using the restriction fragment length polymorphism method. Telomerase activity was detected by using the telomeric repeat amplification protocol. Results: K-ras mutation was positive in 75% (9 of 12) of pancreatic cancers and in 27% (3 of 11) of cases of chronic pancreatitis but in none of the control patients. Telomerase activity was detected in 92% (11 of 12) of pancreatic cancers and in 18% (2 of 11) of cases of chronic pancreatitis. The diagnostic value in pancreatic cancer was comparable between K-ras mutation and telomerase when evaluated separately. However, by combining these 2 methods, the specificity rose to 100%. Conclusions: For the diagnosis of pancreatic cancer, telomerase activity in pancreatic juice may possibly be complementary to K-ras mutation because it may decrease the rate of false-positive diagnosis. (Gastrointest Endosc 2000;51:708-13.)     

Significance of K-ras mutation and CEA level in pancreatic juice in the diagnosis of pancreatic cancer

The early diagnosis of pancreatic carcinoma is essential for increasing patient survival rates. In this study, 52 patients with suspected pancreatic diseases were examined to investigate the value of K‐ras codon 12 point mutation, levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19‐9), and cytology of pancreatic juice in the diagnosis of pancreatic carcinoma. Pancreatic juice was taken without secretin stimulation. K‐ras mutation was detected by enriched polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). K‐ras mutation in pancreatic juice was more frequent in carcinoma than in benign diseases (P = 0.0448). The positive predictive value of K‐ras mutation for the diagnosis of neoplastic disease was 83%. The CEA level in pancreatic juice in carcinoma was significantly greater than that in benign disease (P < 0.0001). When the cutoff level of CEA was set at 50 ng/ml, its accuracy for the diagnosis of carcinoma was 85%. A multivariate analysis showed that K‐ras mutation and CEA level in pancreatic juice, as well as serum CA19‐9 level and age of the patient were independent variables for the diagnosis of carcinoma, and the accuracy of diagnosis by this analysis was increased to 90%. In conclusion, both K‐ras mutation and CEA level in pancreatic juice may be valuable for the diagnosis of carcinoma. Better discrimination was possible with a multivariate analysis.     

胰腺癌患者胰液中K-ras基因突变的检测及其意义

目的 通过对经逆行胰胆管造影（ＥＲＣＰ）所获胰液的Ｋ－ｒａｓ基因突变检测,以探索胰腺癌诊断的新方法。方法 应用聚合酶链反应（ＰＣＲ）－限制性片段长度多态性的方法检测胰腺良、恶性疾病组织物、胰液上清和细胞的Ｋ－ｒａｓ突变。结果 胰腺癌和胰腺良性疾病标本分别有７１％（１５／２１）,而胰腺良性疾病无一例有Ｋ－ｒａｓ的突变。用胰液细胞有４％ＰＣＲ未能获得成功,胰腺癌胰液细胞Ｋ－ｒａｓ的突变率为６５％（１１     

Clinical usefulness of K-ras gene mutation detection and cytology in pancreatic juice in the diagnosis and screening of pancreatic cancer.

BACKGROUND: The significance of K-ras codon 12 mutation in pancreatic juice is still unclear. Although considerable controversy surrounds this question, the diagnostic utility of K-ras in patients with clinical suspicion of pancreatic cancer (PC) and in PC-risk patients remains unknown. OBJECTIVE: To study prospectively the utility of the K-ras gene mutation and cytology in the diagnosis and screening of PC, and to assess its contribution to clinical decision making. METHODS: Pancreatic juice samples obtained from 90 patients were evaluated prospectively. Group I (n = 40) comprised patients with clinical suspicion of PC; group II (n = 50) comprised 49 patients with chronic pancreatitis and one patient proceeding from a PC family screening. The K-ras mutation was detected by means of artificial restriction fragment length polymorphisms (RFLP) in DNA after polymerase chain reaction (PCR) amplification. RESULTS: In group I, of those patients with a definitive diagnosis of PC, malignant cells were found in 27% and K-ras mutation in 44%. In five cases, molecular analysis contributed to diagnosis (4/11 with negative cytology and 1/2 with insufficient cytological material). K-ras mutation revealed an early tumour in one patient, and was the only sample available for diagnosis in another. In group II, the K-ras gene mutation was detected in 8/49 patients (16%) with chronic pancreatitis, one of whom developed PC (2%). CONCLUSIONS: K-ras mutation analysis of pancreatic juice may complement cytological evaluation in the diagnosis of PC, in spite of its limited contribution to clinical decision making. The presence of K-ras mutation in chronic pancreatitis classifies a subgroup of PC-risk patients who should be evaluated carefully by long-term follow-up.     

A meta-analysis of the diagnostic value of detecting K-ras mutation in pancreatic juice as a molecular marker for pancreatic cancer

BackgroundK-ras codon 12 mutation is one of the earliest genetic changes in the development of pancreatic cancer (PC) and accurate detection of K-ras mutations is gaining increasing attention in the field of molecular diagnosis.MethodsOriginal research articles which evaluated the diagnostic accuracy of K-ras mutation detection in PC were selected. Data were presented as forest plots and summary receiver operating characteristic curve analysis was used to summarize the overall test performance.ResultsWe assessed 16 studies from 15 published articles. The pooled sensitivity and specificity were 59% (95%CI: 54%–64%) and 87% (95%CI: 84%–89%), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.13 (95%CI: 2.73–6.25) and 0.42 (95%CI: 0.32–0.56), respectively, and the pooled diagnostic odds ratio was 13.66 (95% CI: 7.25–25.74).ConclusionsOur results indicate that the analysis of K-ras mutations in pancreatic juice has a considerable diagnostic value in PC. Further studies with rigorous design, large sample size, and multi-regional co-operation are needed.     

Telomerase activity in pancreatic juice differentiates pancreatic cancer from chronic pancreatitis: A meta-analysis

Background/objectiveTo evaluate the usefulness of genetic markers in pancreatic juice (PJ), and the combination of these markers with telomerase activity in the differential diagnosis of pancreatic ductal adenocarcinoma (PDAC) from chronic pancreatitis.MethodsWe conducted a meta-analysis for the diagnostic utility of the four major altered genes in PDAC (KRAS, CDKN2A/p16, TP53, and SMAD4/DPC4), telomerase activity, and a combination assay using PJ samples. A literature search was conducted in MEDLINE, Cochrane Library, and Web of Science. Data were pooled and presented as diagnostic sensitivity and specificity with 95% confidence intervals (CIs).ResultsThirty-nine studies fulfilled the inclusion criteria. Pooled estimates of KRAS analysis were as follows: sensitivity was 0.67 (95% CI, 0.63–0.71) and specificity, 0.82 (95% CI, 0.79–0.85). For telomerase activity analysis, sensitivity was 0.82 (95% CI, 0.76–0.87) and specificity, 0.96 (95% CI, 0.90–0.99). The other three tumor suppressors demonstrated low sensitivity. The data did not suggest any publication bias. A combined analysis of KRAS and telomerase activity showed a higher diagnostic sensitivity (0.94; 95% CI, 0.83–0.99) than KRAS alone. A combined analysis of telomerase activity and cytology revealed more reliable diagnostic accuracy than telomerase activity alone, with high sensitivity (0.88; 95% CI, 0.74–0.96) and specificity (1.00; 95% CI, 0.91–1.00).ConclusionsThe most reliable marker in PJ samples for diagnosis of PDAC was telomerase activity. Telomerase activity can play a central role in diagnostic analysis using PJ samples, and can increase diagnostic accuracy when combined with KRAS mutations or cytological examination.     

胰腺癌患者手术标本及胰液脱落细胞端粒酶活性的检测

目的 研究胰腺良，恶性患者手术标本，经ERCP所获胰液脱落细胞的端粒酶活性的表达，探索胰腺癌诊断的新方法。方法 采用TRAP-ELISA的方法检测胰腺癌细胞株，胰腺良恶性疾病组织物，胰液细胞的端粒酶活性。结果 6株胰腺癌细胞株均检测到了端粒酶活性，胰腺癌手术标本端粒酶的阳性率为63%（5/8），而4例正常胰腺组织和2例胰腺良性疾病患者的胰腺标本未检测到端粒酶活性，胰腺癌患者的胰液细胞中，有58%（11/19）检测到有端粒酶活性的表达，而胰腺良性疾病也有高达62.5%(5/8)的阳笥率，两者无差别。结论 胰腺癌组织标本中有较高的端粒酶活性表达；胰液脱落细胞检测端粒酶活性无助于鉴别胰腺良恶性疾病。     

Preproenkephalin hypermethylation in the pure pancreatic juice compared with p53 mutation in the diagnosis of pancreatic carcinoma

Background Aberrant methylation of CpG islands is a common mechanism for the dysregulation of tumor suppressor genes in a variety of human malignancies. Preproenkephalin ppENK) hypermethylation is recognized in 90% of pancreatic carcinoma (PCa) tissues, but not in normal pancreas. We analyzed ppENK hypermethylation in pure pancreatic juice (PPJ) in patients with PCa, intraductal papillary mucinous neoplasms (IPMN), and chronic pancreatitis (CP), and elucidated its usefulness as a marker in the diagnosis of PCa compared with p53 mutation. Methods PPJ was collected endoscopically from 28 patients with PCa, 15 patients with IPMN, and 20 patients with CP. DNA was extracted from the supernatant and the sediment of PPJ. Methylation-specific polymerase chain reaction was performed for hypermethylation analysis of ppENK. In addition, single-strand conformation polymorphism and direct sequencing were performed simultaneously to identify p53 mutations. Results The incidence of ppENK hypermethylation in the supernatant and/or the sediment of PPJ was 50% (14 of 28) in patients with PCa. In contrast, the incidence of ppENK hypermethylation was 26.7% (4 of 15) in patients with IPMN, and 5% (1 of 20) in patients with CP (P < 0.002). The incidence of p53 mutations in the PPJ was 42.9% (12 of 28) in patients with PCa and 0% (0 of 20) in patients with CP. Furthermore, the incidence of ppENK hypermethylation and/or p53 mutations in the PPJ was enhanced to 67.9% (19 of 28) in patients with PCa in the combination assay. Conclusions These results suggest that ppENK hypermethylation in PPJ is specific for cancer, and the combination assay with p53 enhances the genetic diagnosis of PCa.     

Measurement of sialylated stage-specific embryonic antigen-1 in pure pancreatic juice for the diagnosis of pancreatic cancer

The diagnostic significance of measuring sialylated stage-specific embryonic antigen-1 (SLX) in pure pancreatic juice was evaluated in 20 patients with pancreatic cancer, 43 with chronic pancreatitis, 13 with cholecystolithiasis, and 15 control individuals. Four fractions of pure pancreatic juice were collected sequentially from the pancreatic duct by endoscopic cannulation. The SLX levels in all four fractions of pure pancreatic juice were significantly higher in patients with pancreatic cancer than in controls. On the other hand, patients with chronic pancreatitis or cholecystolithiasis did not have SLX levels that significantly differed from those of controls in any fraction. When the cut-off value was set as the mean concentration + 2 times the standard deviation of the control values, the positive rates of SLX in the first fraction (washout phase) and the third fraction (secretory phase) of pure pancreatic juice from pancreatic cancer were 55% (11/20) and 40% (8/20), respectively. Although the false positive rates in the first fraction were high in chronic pancreatitis (30%) and cholecystolithiasis (31%), such high SLX levels in the third fraction were found only in one (2%) patient with chronic pancreatitis and in one (8%) with cholecystolithiasis. The specificities of the test for pancreatic cancer in the first fraction and the third fraction were 70% (39/56) and 96% (54/56), respectively. These results indicate that the measurement of SLX in the third fraction of pure pancreatic juice is useful as a specific marker for pancreatic cancer.     

Significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas

The significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas is still unclear. The aim of this study was to evaluate the significance of K-ras codon 12 point mutation in pancreatic juice in the diagnosis of carcinoma of the pancreas. All of the 78 reports written from 1988 to 1996 on K-ras point mutation of carcinoma, mucin-producing tumors, and hyperplastic epithelia of the pancreas in both surgical or autopsy specimens and pancreatic juice are reviewed. As results, in surgical or autopsy specimens, K-ras mutation was found in 81% of ordinary duct cell carcinoma and in 53% of mucin-producing tumor of the pancreas; this mutation was also found in hyperplastic epithelia in chronic pancreatitis (7%) and in autopsy cases without pancreatic diseases. In pancreatic juice, K-ras mutation was found in 72% of ordinary pancreatic carcinoma and in 53% of mucin-producing tumor, respectively. In conclusion, most previous reports have indicated that K-ras mutation in pancreatic juice is useful for a diagnosis of pancreatic carcinoma. However, since K-ras gene mutation was also detected in non-tumorous lesions, the diagnosis of pancreatic carcinomas is not necessarily correct if it is based solely on the detection of K-ras mutation in pancreatic juice. Future studies should focus on analyzing the amino acid sequence of K-ras mutation or the combination of this mutation with other parameters such as tumor markers in pancreatic juice, to enhance its specificity and accuracy.     

Diagnosis of pancreatic cancer by detecting telomerase activity in pancreatic juice: comparison with K-ras mutations

OBJECTIVE: Telomerase activity is reported to be specific and very frequent in human malignancy. K-ras mutations are also very frequently detected in pancreatic cancer, but their specificity for pancreatic cancer is controversial. We examined the telomerase activity and K-ras mutations in pancreatic juice from patients with pancreatic disease. METHODS: Pancreatic juice was obtained endoscopically at endoscopic retrograde pancreatography from 10 patients with pancreatic cancer, three with chronic pancreatitis, and three with a normal pancreas. The telomerase activity in pancreatic juice was assayed by telomeric repeat amplification protocol. K-ras mutations in exon 1 codon 12 were examined by the two-step polymerase chain reaction combined with restriction enzyme digestion, followed by single-strand conformation polymorphism analysis and direct sequencing. RESULTS: Telomerase activity of >5.0 was detected in eight of 10 (80%) subjects with pancreatic cancer, but in none with chronic pancreatitis or normal pancreas. K-ras mutations were detected not only in eight of 10 (80%) subjects with pancreatic cancer but also in two of three with chronic pancreatitis and in one of three with a normal pancreas. CONCLUSIONS: It was shown that the detection of telomerase activity in pancreatic juice is a more useful diagnostic tool for pancreatic cancer than that of K-ras mutations.     

Detection of K-ras point mutation and telomerase activity during endoscopic retrograde cholangiopancreatography in diagnosis of pancreatic cancer

AIM: To study the value of monitoring K-ras point mutation at codon 12 and telomerase activity in exfoliated cells obtained from pancreatic duct brushings during endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of pancreatic cancer. METHODS: Exfoliated cells obtained from pancreatic duct brushings during ERCP were examined in 27 patients: 23 with pancreatic cancers, 4 with chronic pancreatitis. K-ras point mutation was detected with the polymerase chain reaction and restriction fragment-length polymorphism (PCR-RFLP). Telomerase activity was detected by PCR and telomeric repeat amplification protocol assay (PCR-TRAP-ELISA). RESULTS: The telomerase activities in 27 patients were measured in 21 exfoliated cell samples obtained from pancreatic duct brushings. D450 value of telomerase activities in pancreatic cancer and chronic pancreatitis were 0.446+/-0.27 and 0.041+/-0.0111, respectively. Seventy-seven point eight percent (14/18) of patients with pancreatic cancer and none of the patients with chronic pancreatitis showed telomerase activity in cells collected from pancreatic duct brushings when cutoff value of telomerase activity was set at 2.0. The K-ras gene mutation rate (72.2%) in pancreatic cancer was higher than that in chronic pancreatitis (33.3%) (P<0.05). In considering of both telomerase activities and K-ras point mutation, the total positive rate was 83.3%(15/18), and the specificity was 100%. CONCLUSION: Changes of telomerase activities and K-ras point mutation at codon 12 may be an early event of malignant progression in pancreatic cancer. Detection of telomerase activity and K-ras point mutation at codon 12 may be complementary to each other, and is useful in diagnosis of pancreatic cancer.     

Usefulness of supernatant of pancreatic juice for genetic analysis of K-ras in diagnosis of pancreatic carcinoma

AIMS: To ascertain whether analysis of K-ras mutations at codon 12 (KRM) in the supernatant of pure pancreatic juice (PPJ) is more useful for the diagnosis of pancreatic carcinoma (PCa) than that in sediment, the authors analyzed KRM in DNA extract from not only the sediment but also the supernatant of PPJ and compared the results. METHODOLOGY: PPJ was collected endoscopically from 19 patients with PCa and 25 patients with chronic pancreatitis (CP). DNA was extracted from the supernatant and the sediment of PPJ. Mutant allele-specific amplification (MASA) was performed for KRM analysis with the DNA extracts from these samples. RESULTS: The incidence of KRM in the supernatant of PPJ was 89% (17 of 19) in patients with PCa and 28% (7 of 25) in patients with CP, whereas that in the sediment was 79% (15 of 19) in patients with PCa and 20% (5 of 25) in patients with CP. Although there was no significant difference in KRM incidence between supernatant and sediment, the positive rate of KRM was higher in the former. Additionally, with regard to the PCa cases, KRM were found in the supernatant alone in four cases and in the sediment alone in two cases. Consequently, by a combination assay, all of the patients with PCa showed KRM in either the supernatant or sediment of PPJ. Although there was no relation between the incidence of KRM in PPJ and the location and size of tumor, and clinical stage of carcinoma in the patients with PCa, two patients with clinical stage I disease showed KRM in the supernatant. CONCLUSION: These results suggest that the positive rate of KRM in the supernatant is not lower than that in the sediment, and simultaneous analysis of KRM in the supernatant and sediment of PPJ enhances the genetic diagnosis of PCa.     

Early detection of pancreatic cancer in patients with chronic pancreatitis: diagnostic utility of a K-ras point mutation in the pancreatic juice

OBJECTIVE: Point mutations of the K-ras oncogene at codon 12 have been described several months before the onset of pancreatic cancer in isolated cases of chronic pancreatitis (CP). The aim of this study was to evaluate the interest of a prospective follow-up of patients with CP and K-ras mutations at codon 12 in the detection of early pancreatic cancer. METHODS: From February 1996 to March 1998, 36 patients (mean age 52.6 yr, 31 men, five women) with CP (alcoholic: 61.1%, pancreas divisum: 5.6%, autoimmune: 5.6%, unknown origin: 27.7%) were included and then prospectively monitored (median duration of 22 months) for detection of pancreatic carcinoma. K-ras point mutations were examined by two-step polymerase chain reaction combined with restriction enzyme digestion in pancreatic juice collected during endoscopic retrograde pancreatography. RESULTS: Ten patients (27.8%) were positive for K-ras mutation. Patients with and without the mutation were not different with respect to age and sex ratio. K-ras mutations were homogeneously distributed according to the etiology (alcoholic vs nonalcoholic) and morphological characteristics (ductal stricture or mass vs none) of CP. A pancreatic carcinoma was discovered at an invasive stage in two patients, respectively at 7 and 17 months after disclosure of a K-ras mutation, versus none in patients without the mutation (p < 0.02). CONCLUSIONS: Presence of a K-ras gene mutation is not rare in patients with CP and represents an increased risk of developing pancreatic cancer. However, its utility for the detection of early pancreatic cancer remains doubtful in clinical practice.     

Matrix metalloproteinase-2 in pancreatic juice for diagnosis of pancreatic cancer

INTRODUCTION: Matrix metalloproteinase-2 (MMP-2) has an activity to degrade type IV collagen and is associated with invasion angiogenesis of malignant tumor. AIM: A diagnostic value of MMP-2 in pancreatic juice was studied in the diagnosis of pancreatic cancer. METHODOLOGY: Using gelatin zymography, active MMP-2 and proMMP-2 were determined in pancreatic juice obtained endoscopically from 12 patients with pancreatic cancer, 11 with chronic pancreatitis, and 7 control subjects. RESULTS: ProMMP-2 was detected in 12 of 12 patients (100%) with pancreatic cancer, 6 of 11 (54.5%) with chronic pancreatitis, and 3 of 7 (42.9%) controls. Active MMP-2 was detected in 11 patients (91.6%) with pancreatic cancer, 2 (18.2%) with chronic pancreatitis, and none of the control subjects. An activation ratio of MMP-2 (active MMP-2/total MMP-2) in pancreatic juice is significantly higher in pancreatic cancer (23.4 +/- 4.4%, mean +/- SE) than in chronic pancreatitis (2.1 +/- 1.7%) and controls (0%) (p < 0.01). Active MMP-2 was also detected in pancreatic juice from three cases of small pancreatic cancer (tumor <2 cm in diameter). CONCLUSION: Our observation suggests that detection of active MMP-2 in pancreatic juice using gelatin zymography may be useful for the diagnosis of pancreatic cancer.     

EUS and K-ras analysis of pure pancreatic juice collected via a duodenoscope after secretin stimulation for diagnosis of pancreatic mass lesion: a prospective study

BACKGROUND: The early diagnosis of pancreatic cancer remains problematic. This prospective study assessed the utility of a combination of endoscopic ultrasound (EUS) and genetic analysis of pure pancreatic juice in the diagnosis of pancreatic mass lesions. METHODS: One hundred seventy-six patients with suspected pancreatic disease were enrolled and underwent ultrasonography (US), computed tomography (CT), endoscopic retrograde choleangiopancreatography (ERCP), and EUS. Pure pancreatic juice was collected endoscopically after secretin stimulation. K-ras point mutations at codon 12 in the juice were assayed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Thirty-six (20%) patients were found to have solid pancreatic masses including 19 with cancer (7 patients, 相似文献   

Telomerase activity detected in pancreatic juice 19 months before a tumor is detected in a patient with pancreatic cancer

We report a patient with pancreatic cancer in whom telomerase activity had been detected in the pancreatic juice 19 months before he was diagnosed as having pancreatic cancer. A 61-yr-old alcoholic man complaining of epigastric and back pain was diagnosed as having groove pancreatitis based on the presence of inflammation in the pancreatic head and its extension to the duodenal mucosa with an associated elevated serum amylase level. All imaging modalities showed no sign of a tumor. However, high telomerase activity was detected in the pancreatic juice collected during endoscopic retrograde pancreatography. His symptoms subsided due to abstinence from alcohol. A tumor, however, was recognized on computed tomography 19 months later, at which time the patient immediately underwent a pylorus-preserving pancreaticoduodenectomy. The carcinoma was located mainly in the Santorini duct region. High telomerase activity in the pancreatic juice may precede clinical detection of pancreatic cancer and thus could be a useful early diagnostic marker for pancreatic cancer.