An evaluation of DUPAN-2 in pancreatic cancer and gastrointestinal disease

Using Tumor Marker Gene Variants to Improve the Diagnostic Accuracy of DUPAN-2 and Carbohydrate Antigen 19-9 for Pancreatic Cancer

PURPOSE

Circulating carbohydrate antigen 19-9 (CA19-9) levels reflect FUT3 and FUT2 fucosyltransferase activity. Measuring the related glycan, DUPAN-2, can be useful in individuals unable to synthesize CA19-9. We hypothesized that similar to CA19-9, FUT functional groups determined by variants in FUT3 and FUT2 influence DUPAN-2 levels, and having tumor marker reference ranges for each functional group would improve diagnostic performance.

MATERIALS AND METHODS

Using a training/validation study design, FUT2/FUT3 genotypes were determined in 938 individuals from Johns Hopkins Hospital: 607 Cancer of the Pancreas Screening (CAPS) study subjects with unremarkable pancreata and 331 with pancreatic ductal adenocarcinoma (PDAC). Serum DUPAN-2 and CA19-9 levels were measured by immunoassay.

RESULTS

In controls, three functional FUT groups were identified with significant differences in DUPAN-2 levels: FUT3-intact, FUT3-null/FUT2-intact, and FUT3-null/FUT2-null. DUPAN-2 training set diagnostic cutoffs for each FUT group yielded higher diagnostic sensitivity in the validation set for patients with stage I/II PDAC than uniform cutoffs (60.4% [95% CI, 50.2 to 70.0] v 39.8% [30.0 to 49.8]), at approximately 99% (96.7 to 99.6) specificity. Combining FUT/CA19-9 and FUT/DUPAN-2 tests yielded 78.4% (72.3 to 83.7) sensitivity for stage I/II PDAC, at 97.7% (95.3 to 99.1) specificity in the combined sets, with higher AUC (stage I/II: 0.960 v 0.935 for CA19-9 + DUPAN-2 without the FUT test; P < .001); for stage I PDAC, sensitivity was 62.0% (49.1 to 73.2; AUC, 0.919 v 0.883; P = .03). CA19-9 levels in FUT3-null/FUT2-null PDAC subjects were higher than in FUT3-null/FUT2-intact subjects (median/IQR; 24.9/57.4 v <1/2.3 U/mL; P = .0044). In a simulated CAPS cohort, AUC precision recall (AUCPR) scores were 0.51 for CA19-9 alone, 0.64 for FUT/CA19-9, 0.73 for CA19-9/DUPAN-2, and 0.84 for FUT/CA19-9/DUPAN-2.

CONCLUSION

Using a tumor marker gene test to individualize CA19-9 and DUPAN-2 reference ranges achieves high diagnostic performance for stage I/II pancreatic cancer.

Biomarkers in the diagnosis of pancreatic cancer: Are we closer to finding the golden ticket?

Pancreatic cancer (PC) is a leading cause of cancer related mortality on a global scale. The disease itself is associated with a dismal prognosis, partly due to its silent nature resulting in patients presenting with advanced disease at the time of diagnosis. To combat this, there has been an explosion in the last decade of potential candidate biomarkers in the research setting in the hope that a diagnostic biomarker may provide a glimmer of hope in what is otherwise quite a substantial clinical dilemma. Currently, serum carbohydrate antigen 19-9 is utilized in the diagnostic work-up of patients diagnosed with PC however this biomarker lacks the sensitivity and specificity associated with a gold-standard marker. In the search for a biomarker that is both sensitive and specific for the diagnosis of PC, there has been a paradigm shift towards a focus on liquid biopsy and the use of diagnostic panels which has subsequently proved to have efficacy in the diagnosis of PC. Currently, promising developments in the field of early detection on PC using diagnostic biomarkers include the detection of microRNA (miRNA) in serum and circulating tumour cells. Both these modalities, although in their infancy and yet to be widely accepted into routine clinical practice, possess merit in the early detection of PC. We reviewed over 300 biomarkers with the aim to provide an in-depth summary of the current state-of-play regarding diagnostic biomarkers in PC (serum, urinary, salivary, faecal, pancreatic juice and biliary fluid).

Functional Consequences of Differential O-glycosylation of MUC1, MUC4, and MUC16 (Downstream Effects on Signaling)

Glycosylation is one of the most abundant post-translational modifications that occur within the cell. Under normal physiological conditions, O-linked glycosylation of extracellular proteins is critical for both structure and function. During the progression of cancer, however, the expression of aberrant and truncated glycans is commonly observed. Mucins are high molecular weight glycoproteins that contain numerous sites of O-glycosylation within their extracellular domains. Transmembrane mucins also play a functional role in monitoring the surrounding microenvironment and transducing these signals into the cell. In cancer, these mucins often take on an oncogenic role and promote a number of pro-tumorigenic effects, including pro-survival, migratory, and invasive behaviors. Within this review, we highlight both the processes involved in the expression of aberrant glycan structures on mucins, as well as the potential downstream impacts on cellular signaling.

Cancer-associated carbohydrate antigens for clinical diagnostic markers--its effectiveness and limitations

Cancer cells express various aberrant glycoconjugates. Several kinds of carbohydrate antigens have been used for the serological tumor markers. In particular, the serological level of sialylated carbohydrate antigens, which contain the sialic acid residue in their structure, showed effectiveness in diagnosing cancer behavior. Although large number of carbohydrate antigens in serum of cancer patients was elevated broadly in various cancers, each tumor marker has different sensitivity and specificity for each cancer. Therefore, the combined use of several tumor markers which have different characteristics is effective for better sensitivity in diagnosing cancer behavior. The mechanism of synthesizing cancer-associated carbohydrate antigens is not fully understood because it is very complex. In addition, new cancer-associated carbohydrate antigens are also identified by molecular oncological studies. Those investigations are considered to develop more effective tumor markers to diagnose cancer behavior.

A novel scoring system for arterial invasion of pancreatic body and tail cancer based on multidetector row computed tomography and biomarkers

BACKGROUND/OBJECTIVES

The absence of major-vessel involvement is a crucial factor in the resectability and prognosis of pancreatic cancer. However, arterial invasion cannot be evaluated adequately using imaging findings alone. We therefore developed a scoring system to assess arterial invasion by pancreatic adenocarcinoma using multidetector row computed tomography (MDCT) and serum tumor markers.

METHODS

Twenty patients who underwent distal pancreatectomy and splenectomy for pancreatic adenocarcinoma were examined retrospectively using 4-, 16- or 64-row MDCT and serum tumor markers. Splenic arterial invasion was evaluated in terms of length of tumor contact, circumferential involvement (<180° or ≥180°) and deformity of vascular diameter. Preoperative expression of carbohydrate antigen 19-9 (CA19-9), DUPAN-2 and S-Pancreas-1 antigen (SPan-1) were also evaluated. The presence or absence of arterial invasion was confirmed histopathologically in all 20 cases.

RESULTS

In 11 of 20 cases invasion into splenic arteries was observed histopathologically, mostly involving the external elastic lamina and periarterial nerves. Sensitivity, specificity and accuracy were 100%, 88.9% and 95%, respectively, for length of tumor contact (<16 mm or ≥16 mm), 90.9%, 77.8% and 85% for circumferential involvement (<180° or ≥180°), and 100%, 66.7% and 85% for deformity of vascular diameter. Furthermore, the sensitivity, specificity and accuracy were all increased to 100% when tumor markers were included in the score.

CONCLUSIONS

MDCT is a useful technique for diagnosing arterial invasion of pancreatic body and tail cancer, even in comparison with pathological examination; however, this new scoring system can be further complemented and made more reliable by measurements of serous tumor markers.

Elevated levels of opioid growth factor in the plasma of patients with pancreatic cancer

Opioid growth factor (OGF, [Met5]-enkephalin) is an endogenous peptide that regulates the growth of human pancreatic cancer. To evaluate whether human subjects with pancreatic cancer have alterations in plasma levels of OGF, fasting blood samples were obtained from 15 patients with histologically confirmed pancreatic adenocarcinoma. Forty-five subjects with other malignancies, 20 patients with acute pancreatitis, and 30 aged-matched patients without cancer served as control populations. Individuals with pancreatic cancer had OGF values, as determined by radioimmunoassay, that were up to 7.3-fold greater than control subjects. No differences were found between OGF values obtained from patients with other malignancies, acute pancreatitis, or subjects without cancer. The sensitivity and specificity of OGF for pancreatic cancer were greater than either CA 19-9 or CEA. These data indicate that pancreatic cancer is associated with a marked increase in plasma OGF levels and suggest that this peptide may serve as a useful diagnostic tool in the screening for this disease.

Prospective study of CAM 17.1/WGA mucin assay for serological diagnosis of pancreatic cancer

BACKGROUND

Serological tests for pancreatic cancer are little used, partly because such assays have proved insufficiently specific for screening. However, retrospective studies have reported results that compare well with commonly used scanning techniques. In this prospective study we assessed a new type of combined lectin/antibody enzyme-linked mucin assay, CAM 17.1, in a routine clinical setting.

METHODS

Clinicians at a 1200-bed teaching hospital were encouraged to request the CAM 17.1 assay for any patient whose differential diagnosis included pancreatic cancer. Serum samples from 250 patients were tested during an 18-month period. Patients were followed up for at least 8 months. 75 patients who did not have symptoms of pancreatic cancer and had alternative diagnoses were also studied as a control group.

FINDINGS

Of the 250 patients, 36 had pancreatic cancer, as defined by histological and imaging criteria, and eight of these patients had a resectable tumour. The sensitivity and specificity of the CAM 17.1 assay were 86% and 91%, respectively, in all patients, 85% and 81% in those who presented with jaundice, and 89% and 94% in patients who did not have jaundice. The sensitivity of the assay compared well with that of ultrasound scanning (59%) and computed tomography (83%) in these patients. Use of the CAM 17.1 assay in combination with ultrasonography allowed identification of 94% of patients with pancreatic tumours and all of those with resectable tumours. CAM 17.1 binding activity did not correlate with tumour size.

INTERPRETATION

Our study confirms the usefulness of the CAM 17.1 tumour-marker assay for the diagnosis of pancreatic cancer. Serological mucin assays should be used more widely in combination with ultrasonography in the investigation of non-jaundiced patients with unexplained abdominal pain or weight loss.

Elevated serum levels of Dupan-2 in pancreatic cancer patients negative for Lewis blood group phenotype

CA19-9, a serum marker for pancreatic cancer, gives false-negative results in patients who are negative for the Lewis blood group phenotype. To determine whether other markers may compensate for this drawback, serum levels of CA50, Span-1, sialyl SSEA-1 and Dupan-2 were assayed and compared with those of CA19-9 in 207 normal subjects and in 200 patients with pancreatic carcinoma whose Lewis blood group phenotypes were confirmed. In normal subjects with the Lewis negative phenotype, the serum levels of CA50 and Span-1, as well as CA19-9, were significantly low, whereas those of sialyl SSEA-1 were independent of the Lewis blood group phenotype. Serum levels of Dupan-2 were significantly higher in normal subjects with the Le (a-b-) phenotype as compared with those with Le(a-b+). The sensitivity for pancreatic carcinoma was 81% for CA19-9, 84% for CA50, 82% for Span-1, 51% for sialyl SSEA-1 and 63% for Dupan-2. Among the 39 CA19-9 negative patients, 13 were determined as being Lewis negative by the serum dot-ELISA technique. Although the positive rates were essentially comparable when each marker was combined with CA19-9, a highly elevated serum level of Dupan-2, which strongly suggested the presence of malignancy, was most frequently encountered in 39 patients who were not diagnosed by CA19-9 assay, especially those with Lewis negative blood groups. With regard to the three other markers, we found few patients with a highly elevated serum level in either the Lewis-negative or -positive groups. We conclude that Dupan-2 tended to be elevated in patients with pancreatic cancer who were negative for the Lewis blood group phenotype.