Serum N-glycan profiles in patients with intraductal papillary mucinous neoplasms of the pancreas

N-glycosylation in non-invasive and invasive intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasms (IPMNs), often found incidentally, are potentially malignant cystic tumors of the pancreas. Due to the precancerous nature, IPMNs lacking malignant features should be kept on surveillance. The follow-up relies on magnetic resonance imaging, which has a limited accuracy to define the high-risk patients. New diagnostic methods are thus needed to recognize IPMNs with malignant potential. Here, aberrantly expressed glycans constitute a promising new area of research. We compared the N-glycan profiles of non-invasive IPMN tissues (n = 10) and invasive IPMN tissues (n = 10) to those of non-neoplastic pancreatic controls (n = 5) by matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry. Both IPMN subgroups showed increased abundance of neutral composition H4N4 and decrease in H3N5F1, increase in sialylation, and decrease in sulfation, as compared to the controls. Furthermore, invasive IPMN showed an increase in terminal N-acetylhexosamine containing structure H4N5, and increase in acidic complex-type glycans, but decrease in their complex fucosylation and sulfation, as compared to the controls. In conclusion, the N-glycan profiles differed between healthy pancreatic tissue and non-invasive and invasive IPMNs. The unique glycans expressed in invasive IPMNs may offer interesting new options for diagnostics.

Clinical and Molecular Attributes and Evaluation of Pancreatic Cystic Neoplasm

Intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) are all considered "Pancreatic cystic neoplasms (PCNs)" and show a varying risk of developing into pancreatic ductal adenocarcinoma (PDAC). These lesions display different molecular characteristics, mutations, and clinical manifestations. A lack of detailed understanding of PCN subtype characteristics and their molecular mechanisms limits the development of efficient diagnostic tools and therapeutic strategies for these lesions. Proper in vivo mouse models that mimic human PCNs are also needed to study the molecular mechanisms and for therapeutic testing. A comprehensive understanding of the current status of PCN biology, mechanisms, current diagnostic methods, and therapies will help in the early detection and proper management of patients with these lesions and PDAC. This review aims to describe all these aspects of PCNs, specifically IPMNs, by describing the future perspectives.

The malignant potential of pancreatic intraductal papillary mucinous neoplasm is reflected in expression levels of fucosylated glycans in α1 -acid glycoprotein

BACKGROUND

Pancreatic intraductal papillary mucinous neoplasm (IPMN) involves multiple histopathological stages from benign to malignant lesions. Further, a biomarker to diagnose the malignant IPMN (IPMC) is clinically relevant. Recently, we found that serum fucosylated α₁ -acid glycoprotein (fAGP) level markedly elevated along with disease progression in large cohorts of patients with various cancers.

METHODS

The fAGP level was retrospectively analyzed in preoperative sera from 109 patients with IPMN, and the clinical relevance of fAGP was compared with currently available predictors as standard.

RESULTS

The fAGP level in IPMC was found to be significantly higher than in benign IPMN (P=0.0012). At a cutoff value of 27.04 U/μg, its sensitivity, specificity, and accuracy for IPMC were determined to be 83.61, 65.96 and 75.93%, respectively. Multivariate analyses revealed that the fAGP level was the only independent risk factor for predicting IPMC. Additionally, a combination of the fAGP level and ¹⁸ F-fluorodeoxyglucose uptake on the PET/CT imaging in the lesions seemed to offer the best diagnosis of IPMN. Accordingly, 27 of the 28 patients who were positive in both tests had IPMC, while patients who are negative had benign IPMN.

CONCLUSIONS

The fAGP level appeared to be a relevant biomarker for malignant potential of IPMN.

Recent Advances in Mass Spectrometry-Based Glycomic and Glycoproteomic Studies of Pancreatic Diseases

Modification of proteins by glycans plays a crucial role in mediating biological functions in both healthy and diseased states. Mass spectrometry (MS) has emerged as the most powerful tool for glycomic and glycoproteomic analyses advancing knowledge of many diseases. Such diseases include those of the pancreas which affect millions of people each year. In this review, recent advances in pancreatic disease research facilitated by MS-based glycomic and glycoproteomic studies will be examined with a focus on diabetes and pancreatic cancer. The last decade, and especially the last five years, has witnessed developments in both discovering new glycan or glycoprotein biomarkers and analyzing the links between glycans and disease pathology through MS-based studies. The strength of MS lies in the specificity and sensitivity of liquid chromatography-electrospray ionization MS for measuring a wide range of biomolecules from limited sample amounts from many sample types, greatly enhancing and accelerating the biomarker discovery process. Furthermore, imaging MS of glycans enabled by matrix-assisted laser desorption/ionization has proven useful in complementing histology and immunohistochemistry to monitor pancreatic disease progression. Advances in biological understanding and analytical techniques, as well as challenges and future directions for the field, will be discussed.

Serum N-Glycome analysis reveals pancreatic cancer disease signatures

Background &Aims

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer type with loco‐regional spread that makes the tumor surgically unresectable. Novel diagnostic tools are needed to improve detection of PDAC and increase patient survival. In this study we explore serum protein N‐glycan profiles from PDAC patients with regard to their applicability to serve as a disease biomarker panel.

Methods

Total serum N‐glycome analysis was applied to a discovery set (86 PDAC cases/84 controls) followed by independent validation (26 cases/26 controls) using in‐house collected serum specimens. Protein N‐glycan profiles were obtained using ultrahigh resolution mass spectrometry and included linkage‐specific sialic acid information. N‐glycans were relatively quantified and case‐control classification performance was evaluated based on glycosylation traits such as branching, fucosylation, and sialylation.

Results

In PDAC patients a higher level of branching (OR 6.19, P‐value 9.21 × 10⁻¹¹) and (antenna)fucosylation (OR 13.27, P‐value 2.31 × 10⁻⁹) of N‐glycans was found. Furthermore, the ratio of α2,6‐ vs α2,3‐linked sialylation was higher in patients compared to healthy controls. A classification model built with three glycosylation traits was used for discovery (AUC 0.88) and independent validation (AUC 0.81), with sensitivity and specificity values of 0.85 and 0.71 for the discovery set and 0.75 and 0.72 for the validation set.

Conclusion

Serum N‐glycome analysis revealed glycosylation differences that allow classification of PDAC patients from healthy controls. It was demonstrated that glycosylation traits rather than single N‐glycan structures obtained in this clinical glycomics study can serve as a basis for further development of a blood‐based diagnostic test.

Stage-associated differences in the serum N- and O-glycan profiles of patients with non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer death in China and around the world. Early detection is key to improving the survival rate of non-small cell lung cancer (NSCLC). Alteration in glycosylation has been observed in cancers, and glycans can be a source for the development of new biomarkers for NSCLC.

Methods

In this glycan biomarker discovery study, we measured serum N- and O-glycan profiles in NSCLC patients with different stages and healthy controls by performing lectin microarray analysis. The alterations of serum glycopatterns were compared between NSCLC patients and controls, and the stage-related changes in serum glycosylation were evaluated.

Results

There were 18 lectins (e.g., AAL, Jacalin, GSL-I and DBA) to give significantly alterations of serum glycopatterns in lung adenocarcinoma compared with control group. Meanwhile, 16 lectins (e.g., Jacalin, HHL, and PHA-E+L) exhibited significantly alterations of serum glycopatterns in squamous cell carcinoma (SCC) compared with control group. Importantly, most of the lectins showing altered signals exhibited significantly increased or decreased NFIs in patients with early stage adenocarcinoma and SCC.

Conclusions

The serum glycan profiles were significantly different between NSCLC and healthy control, and most of the glycosylation changes had occurred at early stage. Further evaluation is needed to examine the diagnostic value of the glycan markers identified in this study.

High-density and targeted glycoproteomic profiling of serum proteins in pancreatic cancer and intraductal papillary mucinous neoplasm

OBJECTIVE

Glycoproteomics is an emerging subfield of proteomics. Tumor-specific variations in protein glycosylation might be potential targets for the development of new cancer diagnostics. Here, we performed high-throughput screening and targeted verification of glycome alterations in serum samples from patients with pancreatic cancer and the precancerous lesion intraductal papillary mucinous neoplasm (IPMN).

MATERIAL AND METHODS

The glycosylation profile of 1000 proteins was mapped in a discovery cohort comprising serum samples from 16 individuals, including 8 patients with pancreatic cancer and 8 healthy controls. The top 10 glycoprotein biomarker candidates with the highest signal intensity difference in glycosylation levels were evaluated in a cohort consisting of 109 serum samples, including 49 patients with resectable pancreatic cancer, 13 patients with resectable noninvasive IPMN and 47 healthy controls, using a targeted assay.

RESULTS

Multivariable analysis defined sets of panels comprising CA19-9 and distinctively glycosylated proteins for discrimination between pancreatic cancer, IPMN and healthy controls. A panel including CA 19-9, IL.17E, B7.1 and DR6 gave an AUC of 0.988 at 100% sensitivity at 90% specificity for the discrimination of stage 1 pancreatic cancer and healthy controls. B7.1 was found to be a valuable biomarker for differentiating between IPMN and healthy controls, with better performance alone than CA 19-9.

CONCLUSIONS

Measurement of protein glycosylation profiles in serum may aid in the early detection of pancreatic cancer and precursor lesions.

My Treatment Approach: Pancreatic Cysts

Our treatment approach for either symptomatic or incidentally found pancreatic cysts continues to improve. The true incidence of pancreatic cysts is not known, and pancreatic cystic neoplasms, especially intraductal papillary mucinous neoplasms, are currently most commonly diagnosed and resected. This is a result of increasing awareness, widespread availability of imaging, and better understanding of the nature of pancreatic cysts as well. Recent studies on molecular analysis and devices such as microbiopsy forceps help us better define and select the treatment approach to alleviate symptoms and to prevent malignant tumors while avoiding unnecessary surgery.

Serum tumor markers not useful in screening patients with pancreatic mucinous cystic lesions associated with malignant changes

BACKGROUND

Serum cancer antigen 19-9 (CA19-9) provides additional information about mucinous cystic pancreatic neoplasm (MPN). This study was undertaken to assess both CA19-9 and carcinoembryonic antigen (CEA) serum concentrations in consecutive patients affected by MPNs and other chronic benign and malignant pancreatic diseases. We also evaluated whether serum CA19-9 and CEA determinations provide additional information such as the presence of invasive carcinoma in MPN patients.

METHODS

Serum CA19-9 and CEA from 91 patients with pancreatic diseases were tested by commercially available kits at the time of diagnosis. The upper reference limit of serum CA19-9 was 37 U/mL and that of serum CEA was 3 ng/mL.

RESULTS

Thirty-five patients was diagnosed with chronic pancreatitis (CP), 32 with MPN, and 24 with pancreatic ductal adenocarcinoma (PDAC) confirmed histologically. Surgery was carried out in 5 CP patients, in 10 MPN patients (7 of them had severe dysplasia), and in 9 PDAC patients. Serum CA19-9 activity was high in 12 (34.3%) CP patients, in 7 (21.9%) MPN patients, and in 12 (50.0%) PDAC patients (P=0.089). High serum CEA concentrations were noted in 6 (17.1%) CP patients, in 6 (18.8%) MPN patients, and in 12 (50.0%) PDAC patients (P=0.010). In the 7 MPN patients associated with histologically confirmed severe dysplasia, 3 (42.9%) patients had elevated serum activity of serum CA19-9, and 2 (28.6%) patients had high levels of CEA.

CONCLUSION

Serum determination of oncological markers is not useful in selecting MPN patients with malignant changes.

Pancreatic Cystic Neoplasms: An Update

The incidence of pancreatic cystic neoplasms is rising, in part from detection through the increasing use of high-resolution cross-sectional imaging techniques. Initial diagnosis is generally based on imaging characteristics identified on computed tomography and/or MRI. Endoscopic ultrasound provides further imaging characterization and also enables fluid aspiration and analysis to additionally aid differentiation. The general approach to these lesions includes surgical intervention and/or surveillance imaging. Taking into account diverse presentations, varying malignant potential, and the uncertain natural history of some of these lesions, an evidence-based approach is limited. This article discusses recent updates in the diagnosis and management of cystic neoplasms of the pancreas.