Endoscopic Pancreas Fluid Collection: Methods and Relevance for Clinical Care and Translational Science.

Pancreatic secretions have an important role in the regulation of a normal nutritional state but can be altered owing to a variety of pathophysiological mechanisms in the context of exocrine pancreatic disease. The development of an endoscopic technique for collection of pancreatic fluid, termed endoscopic pancreatic function testing, has led to improved understanding of these alterations and is particularly helpful to characterize chronic pancreatitis. In addition, investigators have found endoscopically collected pancreatic fluid to be a valuable biofluid for the purposes of translational science. Techniques such as proteomic, cytokine, genetic mutation, DNA methylation, and microRNA analyses, among others, can be utilized to gain a better understanding of the molecular characteristics of chronic pancreatitis and other pancreatic diseases. Endoscopic collection of pancreatic fluid is safe and relatively straightforward, permitting opportunities for longitudinal analysis of these translational markers throughout the course of disease. This manuscript summarizes our current knowledge of pancreatic fluid, with an emphasis on proper techniques for sample collection and handling, its clinical utility, and preliminary observations in translational science.

The utility of a novel antibody in the pathological diagnosis of pancreatic acinar cell carcinoma.

AIMS: Acinar cell carcinomas (ACCs) are rare tumours of the exocrine pancreas accounting for about 1-2% of all pancreatic neoplasms in adults. It is therefore difficult to come across a large number of ACC cases in a single medical institution, and only a few serial studies have been published. Since ACCs present a wide variety of morphological patterns, immunohistochemical analysis is useful. In this study, the authors established a novel monoclonal antibody 2P-1-2-1 by means of a subtractive immunisation method. METHODS: Immunohistochemical staining was performed using 50 primary pancreatic tumors, including 7 ACCs, 7 neuroendocrine tumours (NETs), 5 solid-pseudopapillary neoplasms (SPNs), and 31 ductal carcinomas and organs other than the pancreas. RESULTS: Non-neoplastic acinar cells were stained diffusely, but epithelial cells of the pancreatic duct and the islets of Langerhans were not stained. In pancreatic tumours, all the seven ACCs were diffusely positive for the 2P-1-2-1 antibody. However, no positive staining was found in other pancreatic tumours including NETs, SPNs and ductal adenocarcinomas. The sensitivity and specificity of the 2P-1-2-1 antibody for ACCs were both 100%. In other organs studied, positive staining was observed only in the ectopic pancreas. CONCLUSIONS: It was shown that the 2P-1-2-1 antibody specifically stained the pancreatic acinar cells and tumours of acinar cell origin, such as ACCs. Although it remains unclear at this time to which proteins the monoclonal antibody 2P-1-2-1 is directed, it is suggested to be useful for the pathological diagnosis of ACCs and for the exclusion of other pancreatic tumours.

Accuracy of differential diagnosis for pancreatic cancer is improved in the combination of RCAS1 and CEA measurements and cytology in pancreatic juice.

Improvement of diagnostic accuracy for pancreatic cancer in pancreatic disease patients was investigated by examining the combination of three diagnostic methods, i.e., measurements of RCAS1 and CEA levels in pancreatic juice and pancreatic juice cytology. Pancreatic juice was collected from 12 pancreatic cancer (PC) and 26 non-PC patients. RCAS1 and CEA levels were measured by using ELISA. RCAS1 expression on surgically resected tissue was immunohistochemically examined for 2 PC patients. By setting the cutoff level of RCAS1 at 10 U/ml and that of CEA at 18.5 µg/ml, sensitivity of RCAS1 was 42% and that of CEA was 50%. On the other hand, sensitivity and specificity increased from 42% and 85% of RCAS1 alone to 75% and 85% in the examination of RCAS1 + CEA + cytology, and the false-negative rate was also reduced to 25% in this combination. Immunohistochemically, a patient with a high RCAS1 level in pancreatic juice had numerous RCAS1-positive tumor cells in the pancreatic juice. We concluded that RCAS1 and CEA measurements together with cytology in pancreatic juice would be a useful combination method for making a differential diagnosis of PC from non-PC.

Novel monoclonal antibodies against pancreatic juice from pancreatic cancer patients and their possible application in differential diagnosis.

Pancreatic cancer (PC) has a poor clinical prognosis with a <10% 5-year survival rate. Because there are no specific biomarkers of PC, it is difficult to detect small PC tumors and most patients are diagnosed at an advanced stage. Specific biomarkers are useful tools for the early detection of cancer. However, PC-related biomarkers, such as CA19-9 lack specificity and sensitivity. In this study, we took an immunological approach to establish novel monoclonal antibodies (mAbs) specific for the pancreatic juice from PC patients, which would be potentially useful in the diagnosis of PC. Mice were immunized by subtractive immunization using mixed pancreatic juices from chronic pancreatitis and PC patients as the tolerogen and the immunogen, respectively. After screening by Western blotting, four mAbs were obtained: 2P-1-2-1, 2P-1-17-1, 6P-3-2-4 and 7P-9-11-6. The mAb 2P-1-2-1 showed reactivity against the tolerogen at 115 and 120 kDa, but only the 120-kDa antigen was also reactive to the immunogen. The mAb 2P-1-17-1 showed an intense smear reactivity at ~150 kDa against the immunogen. Finally, the mAbs 6P-3-2-4 and 7P-9-11-6 showed PC-specific reactivity to the immunogen at >250 kDa and at ~70 kDa, respectively. We propose that investigation of pancreatic juice samples with these mAbs may enable us to perform reliable differential diagnosis of benign and malignant diseases. Furthermore, we demonstrated that subtractive immunization is a useful method for producing mAbs specific for the pancreatic juice from PC patients.

Transforming growth factor α levels in pancreatic fluid.

UNLABELLED: To determine if the level of transforming growth factor α (TGF-α) in the pancreatic fluid (PF) can diagnose intraductal papillary mucinous neoplasm (IPMN) versus other cystic lesions of the pancreas in patients. METHODS: Pancreatic fluid was prospectively obtained from patients during routine endoscopy and/or operation at Indiana University Hospital. Pancreatic fluid TGF-α levels were analyzed by enzyme-linked immunosorbent assay. Intraductal papillary mucinous neoplasm tissue was also analyzed by TGF-α immunohistochemistry. RESULTS: Sixty-nine fluid samples from 58 patients with the following pathologically confirmed pancreatic disorders were analyzed: IPMN (26 patients), serous cystadenoma (6), mucinous cystic neoplasm (9), pseudocysts (5), non-IPMNY associated pancreatic ductal adenocarcinoma (6), and sphincter of Oddi dysfunction (6). There was no significant difference between the mean PF-TGF-α levels in each category or between different dysplastic grades of IPMN. However, of all the diagnoses examined, only IPMN demonstrated PF-TGF-α levels greater than 95 pg/mL. In low-grade IPMN specimens, TGF-α immunohistochemistry correlated with enzyme-linked immunosorbent assay levels. CONCLUSIONS: The mean PF-TGF-α levels are not significantly different in IPMN lesions compared with those in other cystic pancreatic lesions, pancreatic ductal adenocarcinoma, or sphincter of Oddi dysfunction. However, PF-TGF-α levels more than 95 pg/mL may be useful in diagnosing IPMN. This assertion requires prospective validation.

Oral melatonin attenuates lung inflammation and airway hyperreactivity induced by inhalation of aerosolized pancreatic fluid in rats.

Melatonin is a free radical scavenger with potent antioxidant properties and immunomodulatory effects. The purpose of this study was to determine the effects of orally administered melatonin in a pancreatic fluid (PF)-induced lung inflammation and airway hyperreactivity model. Aerosolized PF was introduced into airways to induce inflammation in rats. Animals were randomized into three experimental groups: sham treated; PF treated (200 µL/kg); and PF with melatonin (10 mg/kg) pretreatment. Airway reactivity to methacholine, airflow and airway resistance, bronchoalveolar lavage (BAL) cellular differential, the tumor necrosis factor α (TNFα) level, lavage nitric oxide, hydroxyl radical, and lactic dehydrogenase (LDH) were compared among groups. mRNA expressions of inducible nitric oxide synthase (iNOS) and TNFα in lung tissues were determined by real-time polymerase chain reaction. Protein expressions of iNOS and nitrotyrosine and lung tissue myeloperoxidase (MPO) activity were determined using an ELISA assay. Oral melatonin treatment indicated anti-inflammatory efficacy as evidenced by decreased methacholine sensitivity by 24% and airway obstruction by 28%, reduction in BAL eosinophil (P < 0.01) and neutrophil counts (P < 0.05), LDH (P < 0.05), and TNFα concentrations (P < 0.05) when compared to levels in sham-treated rats. Melatonin-treated animals also had reduced nitric oxide and hydroxyl radical concentrations (P < 0.05) in lavage fluid. Oral melatonin significantly reduced mRNA and protein expression of iNOS (P < 0.05 and P < 0.01, respectively), TNFα (P < 0.05), nitrotyrosine (P < 0.05), and MPO activity (P < 0.05) in lung tissues when compared with the sham-treated animals. These results suggest that oral treatment with melatonin had a beneficial effect on PF-induced obstructive ventilatory insufficiency by attenuating nitrosative and oxidative stress.

Diagnostic application of CD44 variant expression in pancreatic juice for detection of pancreatic neoplasm.

Recently, increased and disorganized expression of CD44 variant exons (CD44v) has been demonstrated in several types of human malignancy. We tried to investigate CD44v expression in pancreatic juice from patients who underwent endoscopic retrograde pancreatography. We analyzed 24 patients with pancreatic neoplasms diagnosed histologically (adenocarcinoma, 17; adenoma, 7) and 15 patients with non-neoplastic lesions. The expression of CD44v mRNA in pancreatic juice was detected by using the reverse-transcription polymerase chain reaction technique followed by Southern hybridization with exon-specific probes. Of 17 patients with adenocarcinoma, 14 (82%) showed expression of CD44v6 mRNA and 11 (65%) showed expression of CD44v2 mRNA. Of 7 patients with adenoma, 6 (86%) were positive CD44v6 mRNA expression and 2 (29%) for CD44v2 mRNA expression; while, out of 15 patients with non-neoplastic lesion, 5 (33%) showed positive findings for CD44V6 mRNA and 3 (20%) for CD44v2 mRNA. Comparing of diagnostic accuracy among CD44v6, CD44v2 and cytological examination, the sensitivities for adenocarcinoma were 82%, 65% and 41% respectively. However, the specificity was lower in CD44v6 (50%), CD44v2 (77%) than in cytology (100%), because CD44v was positive in adenoma cases and normal cases. A combination of RT-PCR analysis for the expression of CD44v with cytological examination in the pancreatic juice may increase the accuracy of diagnosis for pancreatic cancer.

Secretory immunoglobulin A in pancreatic juice and pancreatic tissue of patients with chronic pancreatitis.

BACKGROUND: The predominance of secretory IgA (S-IgA) in intestinal secretions compared with blood is well established, but concentrations of this protein in pancreatic juice and its origin, especially in chronic pancreatitis, are unknown. AIMS: To investigate the role of S-IgA in chronic pancreatitis. PATIENTS: Twenty one patients with chronic pancreatitis (group I), three patients with proven malignancies (group II), and 12 patients without pancreatic disease (group III). METHODS: Pure human pancreatic juice was collected endoscopically in four fractions after consecutive stimulation with secretin and cholecystokinin (CCK). Samples were analysed for S-IgA, protein, trypsinogen, and proteolytic activity. RESULTS: The S-IgA level was significant increased in fraction 1 of pancreatic juice of group I (1210 (1411) ng/ml) compared with controls (33 (70) ng/ml). Protein concentrations and trypsinogen content were lower in group I than in the other groups. Proteolytic activity could be observed in 53% of all 133 pancreatic juice samples, but in 87% of fraction 1. In pancreatic tissue of three patients with chronic pancreatitis both IgA and secretory component were detected by immunohistology. Expression of the secretory component by human pancreatic epithelial cells was increased in patients with chronic pancreatitis compared with normal controls. The concentration of S-IgA in pancreatic juice did not correlate with the serum S-IgA level. In contrast, serum levels of S-IgA were decreased in patients with chronic pancreatitis. CONCLUSION: There are high levels of S-IgA in human pancreatic juice following chronic inflammation and a protective role is suggested for this immunoglobulin.

Acute pancreatitis in Crohn's disease.

Pancreatitis as an extraintestinal manifestation of Crohn's disease (CD) is controversial. We review the episodes of acute pancreatitis in patients with CD. Of 852 patients, 12 developed clinically overt pancreatitis, representing a frequency of 1.4% in a follow-up period of 10 years. In 10 patients, common causes of pancreatitis were excluded. In 2 patients, drug-induced disease (azathioprine, sulfasalazine) could not be ruled out. Recurrence of pancreatitis was observed in only 2 patients. Younger patients and those with active disease seemed more at risk for development of pancreatitis. If prednisolone was needed for treatment of active CD, no adverse effect was observed for the pancreatitis. Along with the clinical features, we studied autoantibodies against exocrine pancreas; the incidence of autoantibodies in patients with pancreatitis was the same as in the controls who did not develop pancreatic abnormalities. This does not support the hypothesis that acute pancreatitis in CD is associated with the formation of pancreatic autoantibodies.

Diagnostic significance of cancer-associated carbohydrate antigen (CA19-9) concentrations in pancreatic juice: analysis in pure pancreatic juice collected by endoscopic aspiration and immunohistochemical study in chronic pancreatitis.

This study evaluated the diagnostic significance of concentrations of the cancer-associated carbohydrate antigen CA19-9 in pure pancreatic juice (PPJ) collected by endoscopic cannulation. We also attempted to elucidate the features and source of the increased CA19-9 concentration found in the pancreatic juice of patients with chronic pancreatitis (CP) by means of immunohistochemical staining. The mean output as well as the mean concentration of CA19-9 in each of the four fractions collected was highest in patients with pancreatic cancer (PC) and also was elevated significantly in patients with CP compared with controls. However, CA19-9 concentrations were not elevated in patients with cholecystolithiasis. When the cutoff value was set as the mean concentration + 2SD of the controls, significantly elevated concentrations of CA19-9 were found in the third fraction (secretory phase) in 90% of the patients with PC and 66% of the patients with CP. Immunohistochemical staining revealed that CA19-9 was expressed more widely in the ductal cells of CP tissues than in those of normal pancreatic (NP) tissues, with CP tissue showing more CA19-9-positive ductal cells per area than NP tissues. In NP tissue, CA19-9 was localized to the apical surface and supranuclear regions (apical type) in all the ductal cells stained by the antigen, while approximately 50% of cases with CP exhibited a cytoplasmic pattern showing a loss of polarity of the antigen expression. Moreover, this cellular localization pattern was more pronounced in the small ducts that had proliferated and aggregated following the destruction of lobules in CP.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumour antigens CA 195 and CA 19-9 in pancreatic juice and serum for the diagnosis of pancreatic carcinoma.

OBJECTIVE: To see if tumour associated antigens CA 195 and CA 19-9 were able to differentiate between patients with pancreatic carcinoma, and those with chronic pancreatitis or stones in the common bile duct. DESIGN: Prospective, open, clinical study. SETTING: 47 patients with histologically confirmed pancreatic adenocarcinoma, 38 with chronic pancreatitis diagnosed by endoscopic retrograde cholangiopancreatography (ERCP), and 26 with stones in the common bile duct diagnosed and treated by ERCP. INTERVENTIONS: Samples of serum taken from all patients just before ERCP, and samples of pancreatic juice obtained from 18, 11, and 12 patients, respectively during ERCP. RESULTS: Assay of the two tumour markers in pancreatic juice failed to differentiate between patients with benign and malignant disease. When assayed in serum, however, CA 195 detected those with carcinoma with a sensitivity of 72% and a specificity of 92%, and CA 19-9 with a sensitivity of 81% and a specificity of 88%. The patients with unresectable tumours had significantly higher concentrations of both markers in serum than patients with resectable tumours (p less than 0.05). CONCLUSIONS: CA 195 and CA 19-9 concentrations in serum are equally successful in differentiating between benign and malignant pancreatic disease. Assay of markers in pancreatic juice does not provide useful diagnostic information.

Antibodies to a trypsin sensitive pancreatic antigen in chronic inflammatory bowel disease: specific markers for a subgroup of patients with Crohn's disease.

The presence of antibodies against pancreatic juice (PAB) in patients with Crohn's disease has recently been reported. In our study sera from 273 patients with inflammatory bowel disease (222 with Crohn's disease, 51 with ulcerative colitis) have been examined for PAB and also for antibodies against gut tissues by means of indirect immunofluorescence. PAB were found in 68 of the 222 patients with Crohn's disease (31%), with titres ranging from 1/10 to 1/1280, and in only two patients with ulcerative colitis (4%), with titres of 1/20. None were found in 198 patients with various chronic inflammatory diseases and healthy control subjects. No differences were found between the PAB positive and negative patients when the following parameters were compared: disease activity (Crohn's disease activity index), involvement of bowel segments, incidence of extraintestinal disease, or treatment with anti-inflammatory drugs. Only seven of the patients with Crohn's disease had a history of pancreatic disease and of these, four had detectable pancreatic antibodies. Longitudinal observations of 40 patients with Crohn's disease showed a stable pattern for PAB, independent of disease activity and treatment. Partial characterisation of the PAB antigen, isolated from pancreatic juice, showed a trypsin sensitive macromolecular protein of more than 10(6) daltons not identical with a panel of defined exocrine pancreatic proteins. By contrast, antibodies against goblet cells (GAB) were found in 13 of 51 patients with ulcerative colitis (29%) and in none of the patients with Crohn's disease or control subjects. PAB were found as a highly specific serological marker for Crohn's disease and GAB for ulcerative colitis, but the relevance of PAB and GAB in the pathogenesis in Crohn's disease remains unclear.

Mucinous ductal ectasia of the pancreas: a premalignant disease and a cause of obstructive pancreatitis.

Five cases of localized ectasiae of pancreatic ducts associated with epithelial mucinous metaplasia have been previously reported by Itai et al. (Radiology 1986; 161:697-700). During a 1-year period, we collected four new observations of patients presenting with recurrent attacks of pancreatic pain due to similar clusters of cystlike dilated ducts communicating with the main pancreatic duct and lined by a columnar epithelium interspersed with numerous goblet cells. Duct lumina were filled with mucous. Carcinoembryonic antigen levels were high in the pure pancreatic juice, but normal in the blood. Sonography and CT scan showed cystlike, intrapancreatic defects localized three times in the head of the pancreas and once in the body. Endoscopic retrograde cholangiopancreatography (ERCP) showed a huge dilation of some collateral ducts filled by radiolucent defects. The main pancreatic duct was dilated proximally to pathological ducts in three cases. Neither pancreatic stones nor exocrine insufficiency could be demonstrated 7 years after the clinical onset; one case presented with an in situ carcinoma. Since mucinous ductal ectasia is a precancerous state, surgery is mandatory. ERCP is probably the best method of diagnosis.

Significance of adenocarcinoma-associated antigen YH206 levels in the pancreatic juice.

We measured the pancreatic juice levels of antigen YH206, which is a new tumor marker of adenocarcinomas detected by monoclonal antibody YH206 (Hinoda et al., Int. J Cancer 24(5):653-658, 1988). Sandwich enzyme immunoassay revealed that samples from patients with pancreas cancer (n = 21) showed significantly higher values (P less than 0.01) than those of healthy controls (n = 15). Eight out of 21 (38.1%) samples from patients with pancreas cancer showed more than 100 U/ml, whereas only one out of 20 (5.0%) from patients with chronic pancreatitis exhibited more than 100 U/ml of antigen YH206. Simultaneous measurement of antigen YH206 and CA19-9 demonstrated that although a higher incidence of positivity in the case of pancreas cancer was obtained for both antigens, antigen YH206 showed much lower incidence of positivity (14%) than CA19-9 (57%) in patients with chronic pancreatitis. Therefore, the measurement of antigen YH206 in the pancreatic juice could be of use for the diagnosis of pancreas cancer.

[The diagnostic significance of carbohydrate antigen 19-9 in pancreatic carcinomas].

CA 19-9 is a carbohydrate antigen isolated from a human colon carcinoma cell line and reportedly related to gastrointestinal cancers and important for the diagnosis of pancreatic cancer. The present study was aimed at evaluating the diagnostic significance of CA 19-9 by determining serum and pancreatic juice CA 19-9 in 432 and 86 subjects, respectively, including pancreatic cancer patients, normal persons, and patients with a variety of benign and malignant gastrointestinal diseases. An increase of serum CA 19-9 was found in 73% of pancreatic cancer patients, 50% had levels higher than 120 mu/ml, and both of these were significantly higher than normal persons and patients with benign and other malignant diseases. CA 19-9 in the pancreatic juice of pancreatic cancer patients was significantly elevated, whereas in chronic pancreatitis patients it was entirely normal, indicating that CA 19-9 is a valuable tumor marker important for the differential diagnosis of pancreatic cancer.

Estimation of carbohydrate antigen (CA) 19-9 levels in pure pancreatic juice of patients with pancreatic cancer.

Carbohydrate antigen (CA) 19-9 levels in pure pancreatic juice from patients with pancreatic cancer, chronic pancreatitis, and other diseases were determined, and their clinical value was assessed. CA 19-9 levels in pancreatic juice were generally very high, compared with those in serum. In addition, the pancreatic juice CA 19-9 levels in patients with pancreatic cancer were significantly higher than those in patients with chronic pancreatitis and other various diseases used as controls. The assay of pancreatic juice CA 19-9 seemed to be valuable in the diagnosis of pancreatic cancer, showing a diagnostic value approximately similar to that of the serum CA 19-9 assay and clearly superior to that of the serum or pancreatic juice carcinoembryonic antigen assay.

DU-PAN-2 levels in serum and pancreatic ductal fluids of patients with benign and malignant pancreatic disease.

Previous studies have shown that the DU-PAN-2 antigen is elevated in approximately 70% of serum samples obtained from pancreatic adenocarcinoma patients, and within the normal range (less than 400 U/ml) in 99% of normal subjects. In this study, the DU-PAN-2 antigen level of the serum and pancreatic ductal fluid in patients with malignant pancreatic disease were compared to antigen levels in patients with benign pancreatic diseases. Six percent of patients with chronic pancreatitis and 13% of patients with severe acute pancreatitis had elevated DU-PAN-2 antigen levels in their sera. Pancreatic ductal fluid DU-PAN-2 levels were elevated in 33% (11 of 33) of patients with pancreatic adenocarcinomas, whereas 16% (5 of 31) of patients with chronic pancreatitis and 38% (8 of 21) of control patients had elevated secretion levels. Unlike DU-PAN-2, the tumor markers carcinoembryonic antigen (CEA) and carcinoma (CA) 19-9 were elevated in 90 and 100%, respectively, of secretions of patients with pancreatic adenocarcinoma. However, CEA and CA 19-9 ductal fluid levels were also elevated in patients with chronic pancreatitis (CEA: 61%; CA 19-9: 85%), and therefore these markers are not helpful in distinguishing benign from malignant pancreatic disease. The physiologic implications of elevated DU-PAN-2 serum antigen levels in patients with normal ductal fluid DU-PAN-2 levels are discussed.

Complete amino acid sequence of an immunoreactive form of human pancreatic stone protein isolated from pancreatic juice.

The primary structure of a pancreatic stone protein form has been elucidated for the first time. The protein studied was the lowest-Mr form prepared from human pancreatic juice (PSP S1). The N-terminal sequence up to residue 65 had already been determined. The five peptides obtained after staphylococcal protease digestion of the carboxymethylated reduced and succinylated PSP S1 enabled the deduction of the entire sequence. The tryptic peptides arising from the digest of cyclohexanedione--treated PSP S1 and the amino acids released by carboxypeptidase P digestion of PSP S1 confirmed the data of the sequence. The peptides were purified by Sephadex filtration and, if required, by chromatography on DEAE-cellulose or thin-layer cellulose. The amino acid sequences of the peptides were determined with a sequencer. From the sequence data it was deduced that the PSP S1 polypeptide chain contains 133 amino acid residues and has a Mr of 15,000.

Determination of CA 19-9 antigen in serum and pancreatic juice for differential diagnosis of pancreatic adenocarcinoma from chronic pancreatitis.

Serum CA 19-9 levels were measured in 63 patients with ductal pancreatic adenocarcinoma and in 49 patients with chronic pancreatitis. Concentrations were abnormally high (greater than 40 U/ml) in 57 (90%) patients with cancer and only in 5 (10%) patients with chronic pancreatitis. All patients with falsely normal serum values had poorly differentiated carcinomas. Median CA 19-9 concentrations were progressively higher in patients with more advanced cancer. Fifteen of 16 (93%) patients with localized cancer has abnormal serum levels but only 5 (31%) of them had values greater than 120 U/ml, which was the highest score observed in patients with chronic pancreatitis. Pure pancreatic juice was obtained endoscopically from 23 patients with pancreatic cancer and from 20 with chronic pancreatitis. CA 19-9 concentrations in pancreatic juice were significantly higher in patients with cancer than in non-neoplastic patients. All 11 patients with resectable cancer investigated had a ratio of CA 19-9 to secretory protein concentration in pancreatic juice above the range of patients with chronic pancreatitis. We conclude that serum CA 19-9 determination is highly sensitive and specific for the differential diagnosis of pancreatic cancer versus chronic pancreatitis. However, moderately increased values (less than 120 U/ml), as seen in patients with localized pancreatic adenocarcinoma, are not conclusive for malignancy. The measurement of CA 19-9 to total protein ratio in pure pancreatic juice is proposed as an adjunctive, accurate diagnostic marker for early stages of pancreatic adenocarcinoma.