K-Ras and microsatellite marker analysis of fine-needle aspirates from intraductal papillary mucinous neoplasms of the pancreas

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).

Utility of DNA Profiling From Main Pancreatic Duct Fluid by Endoscopic Ultrasound and Endoscopic Retrograde Cholangiopancreatography to Screen for Malignant Potential

OBJECTIVES

The yield of genetic testing of main pancreatic duct (MPD) fluid collected during endoscopic retrograde cholangiopancreatography (ERCP) versus endoscopic ultrasound-guided fine-needle aspiration is unclear.

METHODS

Consecutive MPD fluid samples obtained by endoscopic ultrasound/ERCP with DNA profiling were reviewed, excluding specimens designated "no amplification." Invasive disease included invasive cancer or malignant cytology.

RESULTS

One hundred ten samples from 109 patients who underwent ERCP (n = 32) or endoscopic ultrasound-guided fine-needle aspiration (n = 78) were analyzed (2007-2018). Leading indications were dilated MPD and suspected intraductal papillary mucinous neoplasm. Elevated DNA quantity, KRAS, loss of heterozygosity (LOH), and GNAS mutations occurred in 61.5%, 25.5%, 16.4%, and 8.7% of samples, respectively. Elevated DNA quantity occurred more frequently in ERCP samples (84.4% vs 51.9%, P = 0.002); other mutation yields were similar (P > 0.05). Invasive pathology (P = 0.032) was associated with LOH in the subset of patients who underwent surgery (n = 44). Adverse events occurred more frequently after ERCP (28.1% vs 9.0%, P = 0.016).

CONCLUSIONS

Endoscopic MPD fluid sampling may yield genetic data to improve diagnosis and risk stratification. In our surgical cohort, LOH was the sole predictor of invasive pathology. Endoscopic ultrasound-guided fine-needle aspiration of MPD fluid, when possible, is preferred because of superior safety profile.

Diagnostic Role of F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Characterization of Intraductal Papillary Mucinous Neoplasms: An Updated Systematic Review and Meta-analysis

OBJECTIVES

The purpose of the current study was to investigate the diagnostic performance of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) or PET/computed tomography (CT) for characterization of intraductal papillary mucinous neoplasms (IPMN) through a systematic review and meta-analysis.

METHODS

The PubMed and Embase database were searched for studies evaluating the diagnostic performance of F-18 FDG PET or PET/CT for characterization of IPMN.

RESULTS

Across 14 studies (752 patients), the pooled sensitivity for F-18 FDG PET or PET/CT was 0.84 (95% confidence interval [CI], 0.77-0.89) with heterogeneity (I2 = 55.5, P = 0.01) and a pooled specificity of 0.95 (95% CI, 0.88-0.98) with heterogeneity (I2 = 83.9, P < 0.001). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 17.4 (95% CI, 6.5-46.8) and negative likelihood ratio (LR-) of 0.17 (95% CI, 0.12-0.25). The pooled diagnostic odds ratio was 101 (95% CI, 31-327). Hierarchical summary receiver operating characteristic curve and indicates that the areas under the curve were 0.93 (95% CI, 0.90-0.95).

CONCLUSIONS

The current meta-analysis showed a high sensitivity, specificity, diagnostic odds ratio, and the LR scatter gram of F-18 FDG PET or PET/CT for determination of characteristics of IPMN.

Mutational Mosaics of Cell-Free DNA from Pancreatic Cyst Fluids

BACKGROUND

Pancreatic cyst fluids (PCFs) enriched in tumor-derived DNA are a potential source of new biomarkers. The study aimed to analyze germinal variants and mutational profiles of cell-free (cf)DNA shed into the cavity of pancreatic cysts.

METHODS

The study cohort consisted of 71 patients who underwent endoscopic ultrasound fine-needle aspiration of PCF. Five malignant cysts, 19 intraductal papillary mucinous neoplasms (IPMNs), 11 mucinous cystic neoplasms (MCNs), eight serous cystic neoplasms (SCNs), and 28 pseudocysts were identified. The sequencing of 409 genes included in Comprehensive Cancer Panel was performed using Ion Proton System. The mutation rate of the KRAS and GNAS canonical loci was additionally determined using digital PCR.

RESULTS

The number of mutations detected with NGS varied from 0 to 22 per gene, and genes with the most mutations were: TP53, KRAS, PIK3CA, GNAS, ADGRA2, and APC. The frequencies of the majority of mutations did not differ between non-malignant cystic neoplasms and pseudocysts. NGS detected KRAS mutations in malignant cysts (60%), IPMNs (32%), MCNs (64%), SCNs (13%), and pseudocysts (14%), with GNAS mutations in 20%, 26%, 27%, 13%, and 21% of samples, respectively. Digital PCR-based testing increased KRAS (68%) and GNAS (52%) mutations detection level in IPMNs, but not other cyst types.

CONCLUSIONS

We demonstrate relatively high rates of somatic mutations of cancer-related genes, including KRAS and GNAS, in cfDNA isolated from PCFs irrespectively of the pancreatic cyst type. Further studies on molecular mechanisms of pancreatic cysts malignant transformation in relation to their mutational profiles are required.

Cytologic Analysis of Pancreatic Juice Increases Specificity of Detection of Malignant IPMN-A Systematic Review

BACKGROUND & AIMS

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas can progress to cancer. Biomarkers have been identified that were reported to increase the accuracy of identification of malignant lesions; we performed a systematic review of the accuracy of these markers.

METHODS

We performed a systematic review of published studies on biomarkers of malignant IPMNs by searching MEDLINE and Web of Science databases from January 2005 through December 2017. Our methods were developed based on the Meta-analysis Of Observational Studies in Epidemiology guidelines. Pooled sensitivity, specificity, receiver operating characteristic curves, and their respective areas under the curve (AUC) were calculated from groups of markers (cell-, protein-, or DNA-based) measured in samples collected before and after surgery. A hypothetical test model was developed to determine how to meaningfully amend the revised Fukuoka guidelines, focusing on increasing test specificity for patients with IPMNs that have worrisome features.

RESULTS

We collected data from 193 published studies, comprising 12,297 patients, that analyzed 7 preoperative and 21 postoperative markers of IPMNs. The 3 biomarkers that identified malignant IPMNs with the largest AUC values were pancreatic juice cytology (AUC, 0.84; sensitivity, 0.54; specificity, 0.91), serum protein carbohydrate antigen 19-9 (AUC, 0.81; sensitivity, 0.45; specificity, 0.90), and cyst fluid cytology (AUC, 0.82; sensitivity, 0.57; specificity, 0.84). A combination of cytologic and immunohistochemical analysis of MUC1 and MUC2 in pancreatic juice samples identified malignant IPMNs with the largest AUC and sensitivity values (AUC, 0.85; sensitivity, 0.85; specificity, 0.65). In a test model, inclusion of cytologic analysis of pancreatic juice in the guideline algorithm significantly increased the specificity of detection of malignant IPMNs.

CONCLUSIONS

In a systematic review, we found cytologic analysis of pancreatic juice to have the greatest effect in increasing the specificity of detection of malignant IPMNs. We propose addition of this test to the Fukuoka guidelines for assessment of patients with IPMNs with worrisome features.

Role of Ancillary Testing on Endoscopic US-Guided Fine Needle Aspiration Samples from Cystic Pancreatic Neoplasms

Pancreatic cysts are increasingly detected on imaging studies. Accurate determination of the cyst type is important to provide appropriate care for the patients. It is also very clear that not one single modality can provide adequate diagnostic information. A multidisciplinary approach is the key to the diagnosis of pancreatic cysts. In this setting, the role of ancillary testing, which includes biochemical testing (carcinoembryonic antigen and amylase levels in the cyst), molecular testing (e.g., KRAS, GNAS, VHL, and CTNB1), and/or immunohistochemical tests are very important to obtain an accurate diagnosis. This review will discuss helpful ancillary tests in common pancreatic cyst neoplasms and how to approach the diagnosis of pancreatic cysts.

Genetic testing vs microforceps biopsy in pancreatic cysts: Systematic review and meta-analysis

BACKGROUND

Carcinoembryonic antigen (CEA) and cytology in pancreatic cystic fluid are suboptimal for evaluation of pancreatic cystic neoplasms. Genetic testing and microforceps biopsy are promising tools for pre-operative diagnostic improvement but comparative performance of both methods is unknown.

AIM

To compare the accuracy of genetic testing and microforceps biopsy in pancreatic cysts referred for surgery.

METHODS

We performed a literature search in Medline, Scopus, and Web of Science for studies evaluating genetic testing of cystic fluid and microforceps biopsy of pancreatic cysts, with endoscopic ultrasound with fine-needle aspiration (EUS-FNA) prior to surgery and surgical pathology as reference standard for diagnosis. We evaluated the diagnostic accuracy for: 1- benign cysts; 2- mucinous low-risk cysts; 3- high-risk cysts, and the diagnostic yield and rate of correctly identified cysts with microforceps biopsy and molecular analysis. We also assessed publication bias, heterogeneity, and study quality.

RESULTS

Eight studies, including 1206 patients, of which 203 (17%) referred for surgery who met the inclusion criteria were analyzed in the systematic review, and seven studies were included in the meta-analysis. Genetic testing and microforceps biopsies were identical for diagnosis of benign cysts. Molecular analysis was superior for diagnosis of both low and high-risk mucinous cysts, with sensitivities of 0.89 (95%CI: 0.79-0.95) and 0.57 (95%CI: 0.42-0.71), specificities of 0.88 (95%CI: 0.75-0.95) and 0.88 (95%CI: 0.80-0.93) and AUC of 0.9555 and 0.92, respectively. The diagnostic yield was higher in microforceps biopsies than in genetic analysis (0.73 vs 0.54, respectively) but the rates of correctly identified cysts were identical (0.73 with 95%CI: 0.62-0.82 vs 0.71 with 95%CI: 0.49-0.86, respectively).

CONCLUSION

Genetic testing and microforceps biopsies are useful second tests, with identical results in benign pancreatic cysts. Genetic analysis performs better for low- and high-risk cysts but has lower diagnostic yield.

KRAS in Cyst Fluid Obtained by Endoscopic Ultrasound-Fine-Needle Aspiration in Pancreatic Cystic Lesions: A Systematic Review and Meta-analysis

To evaluate the diagnostic accuracy of KRAS mutation in pancreatic cystic fluid and compare it with carcinoembryonic antigen and cytology, we identified studies with cyst fluid obtained by endoscopic ultrasound prior to surgery. We classified cysts as malignant, premalignant, and benign. A random-effects model was used for quantitative meta-analysis. Pooled sensitivities, specificities, and summary receiver operating characteristic curve analysis were conducted. We analyzed 16 studies, with 3429 patients, including 731 referred for surgery. Carcinoembryonic antigen was better for clinically significant cysts (premalignant and malignant) with sensitivity = 0.58 (95% confidence interval [CI], 0.53-0.65), specificity = 0.9 (95% CI, 0.76-0.97), and area under the curve (AUC) = 0.69. Cytology performed better in malignant cysts, with sensitivity = 0.37 (95% CI, 0.27-0.48), specificity = 0.96 (95% CI, 0.93-0.98), and AUC = 0.78. Isolated, KRAS mutation failed the diagnosis of malignant and significant cysts, with sensitivities = 0.43 (95% CI, 0.34-0.43) and 0.46 (95% CI, 0.42-0.51), specificities = 0.62 (95% CI, 0.56-0.68) and 0.97 (95% CI, 0.92-0.99), and AUCs = 0.56 and 0.53, respectively. Carcinoembryonic antigen and cytology are more accurate than KRAS. Additional studies are lacking to recommend KRAS as a single diagnostic test.

Clinical criteria for integrated molecular pathology in intraductal papillary mucinous neoplasm: less is more

BACKGROUND

For pancreatic cysts with negative cytology, Integrated Molecular Pathology (IMP) is a malignancy risk score integrating clinical criteria with pancreatic cyst fluid DNA profiling. Aside from main pancreatic duct (MPD) diameter, integrated clinical criteria are not International Consensus Guidelines High-Risk Stigmata. We predicted exclusion of clinical criteria except MPD diameter could simplify the IMP and better distinguish invasive/malignant disease.

METHODS

Records of >1100 patients with IPMN were reviewed retrospectively. Sensitivity, specificity, and accuracy of conventional IMP for invasive/malignant disease was compared to DNA profile including only MPD ≥10mm (IMP-10.) Invasive outcomes were invasive-IPMN/adenocarcinoma on surgical pathology, pathologic or radiographic evidence of invasive/metastatic disease during surveillance. Malignant outcomes included high grade dysplastic IPMN (HGD-IPMN).

RESULTS

225 patients who met study criteria underwent 283 IMP evaluations: 98 followed by surgery, 185 followed by ≥ 23 months surveillance. IMP-10 had greater specificity (90.1% vs. 73.7%) and accuracy (89.8% vs. 74.2%) for invasive disease compared to IMP in surgery + surveillance patients, but lower sensitivity (77.8% vs. 88.9%). Trends were similar in surgery patients alone and malignant outcome analyses.

CONCLUSION

IMP-10 excludes less-reliable clinical factors resulting in greater accuracy in predicting invasive/malignant disease and fewer patients with benign disease being recommended for surgery.

Impact of endoscopic ultrasonography on diagnosis of pancreatic cancer

Accumulated evidence has revealed that endoscopic ultrasonography (EUS) has had a great impact on the clinical evaluation of pancreatic cancers. EUS can provide high-resolution images of the pancreas with a quality regarded as far surpassing that achieved on transabdominal ultrasound (US), computed tomography (CT), or magnetic resonance imaging (MRI). EUS is particularly useful for the detection of small pancreatic lesions, while EUS and its related techniques such as contrast-enhanced EUS (CE-EUS), EUS elastography, and EUS-guided fine needle aspiration (EUS-FNA) are also useful in the differential diagnosis of solid or cystic pancreatic lesions and the staging (T-staging, N-staging, and M-staging) of pancreatic cancers. In the diagnosis of pancreatic lesions, CE-EUS and EUS elastography play a complementary role to conventional EUS. When sampling is performed using EUS-FNA, CE-EUS and EUS elastography provide information on the target lesions. Thus, conventional EUS, CE-EUS, EUS elastography, and EUS-FNA are essential in the clinical investigation of pancreatic cancer.

The Use of Biomarkers in the Risk Stratification of Cystic Neoplasms

Cyst fluid biomarkers may be used to identify pancreatic cyst subtypes. Biomarkers are selected based on their ability to accurately distinguish mucinous from nonmucinous cysts and to risk stratify cysts based on malignant potential. Biomarkers of interest include but are not limited to amylase, oncogenes, DNA analysis, and epigenetic markers. The introduction of next-generation sequencing and molecular panels has aided in improved diagnostic accuracy and risk stratification. This review presents the diagnostic performance of currently available biomarkers and proposes an algorithm to incorporate their use in the diagnosis of pancreatic cysts.

DNA profile components predict malignant outcomes in select cases of intraductal papillary mucinous neoplasm with negative cytology

BACKGROUND

Predicting malignancy in intraductal papillary mucinous neoplasm remains challenging. Integrated molecular pathology combines pancreatic fluid DNA and clinical factors into a malignant potential score. We sought to determine the utility of DNA components alone in predicting high-grade dysplasia/invasive disease.

METHODS

We reviewed prospectively the records from 1,106 patients with intraductal papillary mucinous neoplasm. We excluded non-intraductal papillary mucinous neoplasm cases and cases with definitive malignant cytology. A total 225 patients had 283 DNA profiles (98 followed by surgery, 185 followed by ≥23-month surveillance). High-grade dysplasia/invasive outcomes were high-grade dysplasia, intraductal papillary mucinous neoplasm-invasive, and adenocarcinoma on surgical pathology or mesenteric or vascular invasion, metastases, or biopsy with high-grade dysplasia or adenocarcinoma during surveillance.

RESULTS

High-quantity DNA predicted (P = .004) high-grade dysplasia/invasive disease outcomes with sensitivity of 78.3%, but 52.7% specificity, indicating benign cases may exhibit high-quantity DNA. High clonality loss of heterozygosity of tumor suppressor genes was 98.0% specific, strongly predicted high-grade dysplasia/invasive disease but lacked sensitivity (20.0%). High-quantity DNA + high clonality loss of heterozygosity had 99.0% specificity for high-grade dysplasia/invasive disease. KRAS mutation alone did not predict high-grade dysplasia/invasive disease, but, when combined with high-quantity DNA (specificity 84.7%) and high clonality loss of heterozygosity (specificity 99.0%) strongly predicted high-grade dysplasia/invasive outcomes.

CONCLUSION

Certain DNA components are highly specific for high-grade dysplasia/invasive disease and may indicate aggressive lesions, requiring resection when cytology fails.

Confocal endomicroscopy and cyst fluid molecular analysis: Comprehensive evaluation of pancreatic cysts

Increases in the quality as well as utilization of cross-sectional imaging have led to rising diagnoses of pancreatic cystic lesions (PCL). Accurate presurgical diagnosis enables appropriate triage of PCLs. Unfortunately, current diagnostic approaches have suboptimal accuracy and may lead to unnecessary surgical resections or missed diagnoses of advanced neoplasia. Additionally, early detection represents an opportunity for intervention to prevent the progression to pancreatic adenocarcinoma. Our aim for this review is to systematically review the current literature on confocal endomicroscopy and molecular biomarkers in the evaluation of PCLs. Confocal laser endomicroscopy is a novel technology that allows for real-time in vivo microscopic imaging with multiple clinical trials identifying characteristic endomicroscopy findings of various pancreatic cystic lesions. DNA-based molecular markers have also emerged as another diagnostic modality as the pattern of genetic alternations present in cyst fluid can provide both diagnostic and prognostic data. We propose that both techniques can be utilized to improve patient outcomes.

Endoscopic Ultrasound Imaging for Diagnosing and Treating Pancreatic Cysts

Cystic pancreatic lesions are increasingly diagnosed owing to the abundant use of cross-sectional imaging. Given their malignant potential, true pancreatic cysts should be considered for resection or periodic follow-up. Cystic lesions of the pancreas (CLPs) require further evaluation and management. Therefore, it is important to establish a solid diagnosis at the time of detection. Endoscopic ultrasound examination is the imaging modality of choice. Fine needle aspiration provides fluid for cytologic, biochemical, and molecular assays to classify lesions and predict biological behavior. This review provides an overview of the diagnosis and management of various types of commonly encountered true CLPs.

Molecular analysis of mucinous nonneoplastic cyst of the pancreas

Although a mucinous nonneoplastic cyst (MNNC) of the pancreas is defined as a benign nonneoplastic lesion with no malignant potential, its histogenesis and etiology are still uncertain. To explore the origin and development of MNNC, we searched for neoplasia-associated mutational change in oncogene and tumor suppressor genes. Specifically, we analyzed KRAS oncogene mutations by polymerase chain reaction/dideoxy DNA (Sanger) sequencing and tumor suppression gene deletion by loss of heterozygosity (LOH) using polymerase chain reaction/capillary gel electrophoresis for a panel of 16 polymorphic microsatellite repeat markers targeting common tumor suppression gene loci at 1p, 3p, 5q, 9p, 10q, 17p, 17q, 18q, 21q, and 22q on DNA isolated from the cystic lining epithelium microdissected from 15 surgically diagnosed MNNCs by microdissection of unstained histologic sections of fixed resection specimens. DNA mutations were demonstrated in 4 of 15 cases: 1 with KRAS mutation at codon 12 glycine (G) substitution by aspartic acid (D) (G12D), 1 with KRAS mutation at 12 glycine (G) substitution by arginine (R) (G12R), 1 with LOH at 10q (PTEN), and 1 with LOH at 17q (RNF43). Therefore, although the genomic mutation rate detected in MNNC is relatively low, our results indicate that MNNCs may acquire genetic alteration similar to low-grade pancreatic intraepithelial neoplasia, furthering debate of the true nature of these lesions.

Expansion of epigenetic alterations in EFEMP1 promoter predicts malignant formation in pancreatobiliary intraductal papillary mucinous neoplasms

Purpose

Although limited understanding exists for the presence of specific genetic mutations and aberrantly methylated genes in pancreatobiliary intraductal papillary mucinous neoplasms (IPMNs), the fundamental understanding of the dynamics of methylation expansion across CpG dinucleotides in specific gene promoters during carcinogenesis remains unexplored. Expansion of DNA methylation in some gene promoter regions, such as EFEMP1, one of the fibulin family, with tumor progression has been reported in several malignancies. We hypothesized that DNA hypermethylation in EFEMP1 promoter would expand with the tumor grade of IPMN.

Methods

A sample of 65 IPMNs and 30 normal pancreatic tissues was analyzed. IPMNs were divided into the following three subsets according to pathological findings: 31 with low-grade dysplasia (low grade), 11 with high-grade dysplasia (high grade), and 23 with associated invasive carcinoma (invasive Ca). Mutations in the KRAS or GNAS genes were analyzed by Sanger sequencing, and methylation status of two discrete regions within the EFEMP1 promoter, namely region 1 and region 2, was analyzed by bisulfite sequencing and fluorescent high-sensitive assay for bisulfite DNA (Hi-SA). Expression status of EFEMP1 was investigated by immunohistochemistry (IHC).

Results

KRAS mutations were detected in 39, 55, and 70 % of low-grade, high-grade, and invasive Ca, respectively. GNAS mutations were observed in 32, 55, and 22 % of low-grade, high-grade, and invasive Ca, respectively. The methylation of individual regions (region 1 or 2) in the EFEMP1 promoter was observed in 84, 91, and 87 % of low-grade, high-grade, and invasive Ca, respectively. However, simultaneous methylation of both regions (extensive methylation) was exclusively detected in 35 % of invasive Ca (p = 0.001) and five of eight IPMNs (63 %) with extensive methylation, whereas 20 of 57 (35.1 %) tumors of unmethylation or partial methylation of the EFEMP1 promoter region showed weak staining EFEMP1 in extracellular matrix (p = 0.422). In addition, extensive EFEMP1 methylation was particularly present in malignant tumors without GNAS mutations and associated with disease-free survival of patients with IPMNs (p < 0.0001).

Conclusions

Extensive methylation of the EFEMP1 gene promoter can discriminate invasive from benign IPMNs with superior accuracy owing to their stepwise accumulation of tumor progression.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2164-x) contains supplementary material, which is available to authorized users.

Molecular Analyses of Aspirated Cystic Fluid for the Differential Diagnosis of Cystic Lesions of the Pancreas: A Systematic Review and Meta-Analysis

Background. Researchers have evaluated various molecular tests for improving the differential diagnosis of cystic lesions of the pancreas. Methods. Six electronic databases were searched for articles on molecular tests for the diagnosis of pancreatic cysts. Measures of accuracy were extracted from selected articles and pooled by the random-effects model. Summary receiver operating characteristic curves were used to analyze the overall accuracy of the molecular tests. Pooled sensitivity and specificity values [95% confidence intervals] are reported. Results. The systematic review included eight studies of 428 patients in total. We determined the sensitivities and specificities of tests for KRAS mutations (0.47 [0.39-0.54], 0.98 [0.93-0.99]) and loss of heterozygosity (0.63 [0.54-0.71], 0.76 [0.63-0.87]) for distinguishing mucinous from nonmucinous cysts, as well as the sensitivities and specificities of tests for KRAS mutations (0.59 [0.46-0.71], 0.78 [0.71-0.85]) and loss of heterozygosity (0.89 [0.78-0.96], 0.69 [0.60-0.76]) for differentiating malignant from benign cysts. Conclusion. Tests of KRAS mutations could confirm but not exclude a diagnosis of a mucinous or malignant pancreatic cyst.

Role of emerging molecular markers in pancreatic cyst fluid

Cystic lesions of the pancreas (CLPs) are increasingly diagnosed due to the growing utilization of cross-sectional imaging modalities. The differentiation between true cysts (epithelial tumors) and nonepithelial lesions (such as pseudocysts) relies on clinical and imaging characteristics, but more reliably obtained by endoscopic ultrasound (EUS) fine-needle aspiration. Due to their malignant potential, some of the true pancreatic cysts require further assessment and periodic follow-up. Therefore, it is important to establish a solid diagnosis at the time of detection of the various types of pancreatic cysts. Due to the limitations of cytology and biochemical markers in accurately classifying cyst pathology, the search for specific molecular markers associated with each type of cyst is ongoing. In this chapter, we will review some of the emerging molecular markers in pancreatic cystic fluid and their potential impact on endosonography and pancreatic cyst management.

Pathology, genetics and precursors of human and experimental pancreatic neoplasms: An update

Over the past decade, there have been substantial improvements in our knowledge of pancreatic neoplasms and their precursor lesions. Extensive genetic analyses, recently using high-throughput molecular techniques and next-generation sequencing methodologies, and the development of sophisticated genetically engineered mouse models closely recapitulating human disease, have improved our understanding of the genetic basis of pancreatic neoplasms. These advances are paving the way for refined, molecular-based classifications of pancreatic neoplasms with the potential to better predict prognosis and, possibly, response to therapy. Another major development resides in the identification of subsets of pancreatic exocrine and endocrine neoplasms which occur in the context of hereditary syndromes and whose genetic basis and tumor development have been at least partially defined. However, despite all molecular progress, correct and careful morphological characterization of tissue specimens both in the context of experimental and routine diagnostic pathology represents the basis for any further genetic investigation or clinical decision. This review focuses on the current and new concepts of classification and on the current models of tumor development, both in the field of exocrine and endocrine neoplasms, and underscores the importance of applying standardized terminology to allow adequate data interpretation and promote scientific exchange in the field of pancreas research.

Systematic Review of Pancreatic Cyst Fluid Biomarkers: The Path Forward

There is significant research interest in developing and validating novel pancreatic cyst-fluid biomarkers given the increasing recognition of the prevalence of pancreatic cysts and their associated malignant potential. Although current international consensus guidelines are helpful, they fail to diagnose with certainty the cyst type and the level of epithelial dysplasia. They also fall short in predicting the future likelihood of malignant transformation. A systematic review was performed with the objective of summarizing cyst-fluid-based biomarkers that have been published in the medical literature over the past 10 years and characterizing the current quality of evidence. Our review demonstrates that there is an increasing interest in this topic with several different and innovative approaches including DNA, RNA, proteomic, and metabolomics profiling. Further techniques to improve upon cytological yield have also been studied. Besides identifying potentially useful clinical biomarkers, these empiric approaches have provided further insight into their pathogenesis. The level of evidence for the vast majority of these studies, however, is limited to retrospective early validation studies. The path forward will be to select out the most promising biomarkers and develop multicenter consortiums capable of capturing adequate sample sizes with appropriate study designs.

Cystic neoplasms of the pancreas; findings on magnetic resonance imaging with pathological, surgical, and clinical correlation

Pancreatic cysts are increasingly being identified by cross-sectional imaging studies. Pancreatic cystic lesions comprise a spectrum of underlying pathologies ranging from benign and pre-malignant lesions to frank malignancies. Magnetic resonance imaging with cholangiopancreatography is a non-invasive imaging modality used for the characterization of cystic pancreatic lesions. This article will review the most common pancreatic cystic neoplasms and the utility of MR imaging in the characterization of these cysts.

Does EUS-FNA molecular analysis carry additional value when compared to cytology in the diagnosis of pancreatic cystic neoplasm? A systematic review

BACKGROUND

Endoscopic ultrasonography with fine needle aspiration (EUS-FNA) has become an integral tool in the diagnosis of pancreatic cystic lesions (PCLs) and the analysis of molecular/DNA abnormalities might improve the accuracy of pre-operative diagnosis. A review was conducted of all studies using EUS-FNA aspirates of PCLs to assess the accuracy and added benefit that molecular analysis provides to cytological analysis.

METHODS

A systematic review of the literature was conducted using PRISMA guidelines and electronic databases: PubMed/SCOPUS/EMBASE/Cochrane/CINAHL. Surgical pathology was used as the definitive reference standard. The QUADAS-2 tool was used for quality assessment.

RESULTS

In total, 162 articles were identified; 12 articles met inclusion/exclusion criteria. Ten studies reported on cytology and 8 studies reported k-ras mutational analysis. 362 patients (of 1115 total) had surgical pathology available. The sensitivity and specificity of cytology was 0.42 and 0.99; the sensitivity and specificity of k-ras was 0.39 and 0.95; and the sensitivity and specificity of the combined test of cytology and k-ras was 0.71 and 0.88, respectively.

CONCLUSIONS

k-ras mutational analysis used as an individual screening test has a poor diagnostic accuracy, as does cytology when used alone. The benefit comes with utilization in a combined fashion. More studies are needed to evaluate the correct sequence and utility of these tests for cyst differentiation.

Management of serous cystic neoplasms of the pancreas

Pancreatic serous cystadenomas are uncommon benign tumours that are often found incidentally on routine imaging examinations. Radiological imaging techniques alone have proven to be suboptimal to fully characterize cystic pancreatic lesions. Endoscopic ultrasound, with the addition of fine-needle aspiration in difficult cases, has showed greater diagnostic accuracy than conventional imaging techniques. The best management strategy of these neoplasms is still debated. Surgery should be limited only to symptomatic and highly selected cases and most of the patients should only be strictly monitored. In the current paper, we provide an updated overview on pancreatic serous cystadenomas, focusing our attention on epidemiology, clinical characteristics and diagnostic evaluation; finally, we also discuss different management strategies and areas for future research.

Is it safe to follow side branch IPMNs?

Management of Bd-IPMN remains challenging. Critical appraisal of the published literature reveals that the actual treatment of what is presumed to be Bd-IPMN remains unsatisfactory, with a high rate of surgically overtreated patients. Until we accrue more precise knowledge of the natural history of Bd-IPMN, management of patients with this presumed diagnosis should be individually tailored and preferably carried out in centers with a high expertise. For now, the authors strongly think that the old guidelines should be followed in most patients because these have proven to correctly identify lesions that can be safely followed. Although the new guidelines allow for follow-up of lesions greater than 3 cm, and for the most part this is safe, they should be used cautiously in younger patients because very close surveillance would be required for their long remaining lifespan.

Moving beyond morphology: new insights into the characterization and management of cystic pancreatic lesions

The frequency of detection of cystic pancreatic lesions with cross-sectional imaging, particularly with multidetector computed tomography, magnetic resonance (MR) imaging, and MR cholangiopancreatography, is increasing, and many of these cystic pancreatic lesions are being detected incidentally in asymptomatic patients. Because there is considerable overlap in the cross-sectional imaging findings of cystic pancreatic lesions, and because many of these lesions being detected are smaller than 3 cm in diameter and lack any specific cross-sectional imaging features, it has become difficult to make informed decisions about patient management when the precise diagnosis remains uncertain. This article presents the limitations of cross-sectional imaging in patients with cystic pancreatic lesions, details advances in knowledge of the genomic and epigenomic changes that lead to progression of carcinogenesis, outlines the current understanding of the natural history of mucinous cystic lesions, and includes the current use and future potential of novel tumor markers and molecular analysis to characterize cystic pancreatic lesions more precisely. The need to move beyond cross-sectional imaging morphology and toward the use of new techniques to diagnose these lesions accurately is emphasized. An algorithm that uses these techniques is proposed and will hopefully lead to improved patient management.

The added value of using mutational profiling in addition to cytology in diagnosing aggressive pancreaticobiliary disease: review of clinical cases at a single center

Background

This study aimed to better understand the supporting role that mutational profiling (MP) of DNA from microdissected cytology slides and supernatant specimens may play in the diagnosis of malignancy in fine-needle aspirates (FNA) and biliary brushing specimens from patients with pancreaticobiliary masses.

Methods

Cytology results were examined in a total of 30 patients with associated surgical (10) or clinical (20) outcomes. MP of DNA from microdissected cytology slides and from discarded supernatant fluid was analyzed in 26 patients with atypical, negative or indeterminate cytology.

Results

Cytology correctly diagnosed aggressive disease in 4 patients. Cytological diagnoses for the remaining 26 were as follows: 16 negative (9 false negative), 9 atypical, 1 indeterminate. MP correctly determined aggressive disease in 1 false negative cytology case and confirmed a negative cytology diagnosis in 7 of 7 cases of non-aggressive disease. Of the 9 atypical cytology cases, MP correctly diagnosed 7 as positive and 1 as negative for aggressive disease. One specimen that was indeterminate by cytology was correctly diagnosed as non-aggressive by MP. When first line malignant (positive) cytology results were combined with positive second line MP results, 12/21 cases of aggressive disease were identified, compared to 4/21 cases identified by positive cytology alone.

Conclusions

When first line cytology results were uncertain (atypical), questionable (negative), or not possible (non-diagnostic/indeterminate), MP provided additional information regarding the presence of aggressive disease. When used in conjunction with first line cytology, MP increased detection of aggressive disease without compromising specificity in patients that were difficult to diagnose by cytology alone.

The value of mutational profiling of the cytocentrifugation supernatant fluid from fine-needle aspiration of pancreatic solid mass lesions

Fine-needle aspiration (FNA) of pancreatic solid masses can be significantly impacted by sampling variation. Molecular analysis of tumor DNA can be an aid for more definitive diagnosis. The aim of this study was to evaluate how molecular analysis of the cell-free cytocentrifugation supernatant DNA can help reduce sampling variability and increase diagnostic yield. Twenty-three FNA smears from pancreatic solid masses were performed. Remaining aspirates were rinsed for preparation of cytocentrifuged slides or cell blocks. DNA was extracted from supernatant fluid and assessed for DNA quantity spectrophotometrically and for amplifiability by quantitative PCR (qPCR). Supernatants with adequate DNA were analyzed for mutations using PCR/capillary electrophoresis for a broad panel of markers (KRAS point mutation by sequencing, microsatellite fragment analysis for loss of heterozygosity (LOH) of 16 markers at 1p, 3p, 5q, 9p, 10q, 17p, 17q, 21q, and 22q). In selected cases, microdissection of stained cytology smears and/or cytocentrifugation cellular slides were analyzed and compared. In all, 5/23 samples cytologically confirmed as adenocarcinoma showed detectable mutations both in the microdissected slide-based cytology cells and in the cytocentrifugation supernatant. While most mutations detected were present in both microdissected slides and supernatant fluid specimens, the latter showed additional mutations supporting greater sensitivity for detecting relevant DNA damage. Clonality for individual marker mutations was higher in the supernatant fluid than in microdissected cells. Cytocentrifugation supernatant fluid contains levels of amplifiable DNA suitable for mutation detection and characterization. The finding of additional detectable mutations at higher clonality indicates that supernatant fluid may be enriched with tumor DNA. Molecular analysis of the supernatant fluid could serve as an adjunct method to reduce sampling variability and increase diagnostic yield, especially in cases with a high clinical suspicion for malignancy and limited number of atypical cells in the smears.

Pancreatic cancer genomes: toward molecular subtyping and novel approaches to diagnosis and therapy

Pancreatic neoplasms represent a broad range of clinical entities, many of which have drastic effects on the lives of patients. Recently, high-throughput sequencing analyses have been performed in many pancreatic neoplasms, providing deep insights into the underlying biology of these neoplasms as well as novel approaches to diagnosis and treatment. This review discusses the molecular alterations underlying pancreatic neoplasms as well as the clinical impact of these alterations for diagnosis and treatment.

Performance characteristics of molecular (DNA) analysis for the diagnosis of mucinous pancreatic cysts

BACKGROUND

Diagnosis of mucinous pancreatic cysts (MPCs) is challenging due to the poor sensitivity of cytology provided by EUS-guided-FNA (EUS-FNA).

OBJECTIVE

To quantify the test characteristics of molecular (DNA) analysis in suspected low-risk MPCs.

DESIGN

A prospective cohort study performed in between 2008 and 2011.

SETTING

Academic referral center.

PATIENTS

Consecutive patients who underwent EUS-FNA of suspected MPCs.

INTERVENTION

EUS-FNA and molecular (DNA) analysis of cyst fluid.

MAIN OUTCOME MEASUREMENTS

The sensitivity and specificity of molecular analysis in the diagnosis of MPCs using the criterion standard of surgical pathology in resected cysts.

RESULTS

Patients with suspected MPCs underwent EUS-FNA and cyst fluid DNA analysis. Surgical resection was performed in 48 patients (17%), confirming a mucinous pathology in 38 (79%). In this group, molecular analysis had a sensitivity of 50% and a specificity of 80% in identifying MPCs (accuracy of 56.3%). The combination of molecular analysis with cyst fluid carcinoembryonic antigen (CEA) and cytology resulted in higher MPC diagnostic performance than either one of its individual components, with a sensitivity, specificity, and accuracy of 73.7%, 70%, and 72.9%, respectively. There was no significant difference in accuracy between molecular analysis and CEA/cytology in this group.

LIMITATIONS

Single-center experience.

CONCLUSION

Molecular analysis aids in the diagnosis of MPCs when cytology is nondiagnostic or cyst fluid is insufficient for CEA or its level is indeterminate. Our results do not support the routine use of molecular analysis, which should be used selectively after review of imaging findings and cyst fluid studies. Further studies are needed to assess DNA's performance in malignant cysts.

Mutational analysis of cytocentrifugation supernatant fluid from pancreatic solid mass lesions

Diagnosis of fine-needle aspirations of pancreatic solid masses is complicated by many factors that keep its false-negative rate high. Our novel approach analyzes cell-free cytocentrifugation supernatant, currently a discarded portion of the specimen. Supernatant and cytology slides were collected from 25 patients: 11 cases with confirmed outcome [five positive (adenocarcinoma) and six negative (inflammatory states)], plus 14 without confirmed outcomes. Slides were microdissected, DNA was extracted from microdissections and corresponding supernatants, and all were analyzed for KRAS point mutation and loss of heterozygosity. Notably, higher levels of free DNA were found in supernatants than in corresponding microdissected cells. Supernatants contained sufficient DNA for mutational profiling even when samples contained few to no cells. Mutations were present in 5/5 malignancies and no mutations were present in inflammatory states. In conclusion, these findings support using supernatant for mutational genotyping when diagnostic confirmation is required for pancreatic solid masses. Diagn. Cytopathol. 2014;42:719–725. © 2013 Wiley Periodicals, Inc.

Integration of KRAS testing in the diagnosis of pancreatic cystic lesions: a clinical experience of 618 pancreatic cysts

With improvements in abdominal imaging, detection of incidental pancreatic cysts are becoming increasingly common. Analysis of pancreatic cyst fluid from fine-needle aspiration is particularly important in identifying intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), which have significant implications in clinical intervention and follow-up. Previous controlled studies have shown that KRAS mutations in cyst fluid are highly specific for mucinous differentiation in pancreatic cysts; however, this has not been examined in the clinical setting. Over a 6-year study period, 618 pancreatic cyst fluids obtained by fine-needle aspiration at the time of endoscopic ultrasound were tested for KRAS mutations as part of routine evaluation for a cystic neoplasm. Of the 618 specimens, 603 (98%) from 546 patients were satisfactory for molecular analysis. Patients ranged in age from 17 to 90 years (mean, 63.9 years) and were predominantly female (68%). Pancreatic cysts were relatively evenly distributed throughout the pancreas and ranged in size from 0.6 to 11.0 cm (mean, 2.3 cm). Mutations in KRAS were detected in 232 of 603 (38%) aspirates. Although sufficient for molecular analysis, 320 of 603 (53%) specimens were either less than optimal (38%) or unsatisfactory (15%) for cytopathologic diagnosis. Surgical follow-up information was available for 142 (26%) patients and consisted of 53 KRAS-mutated and 89 KRAS-wild-type cysts. Overall, KRAS mutations had a specificity of 100%, but a sensitivity of 54% for mucinous differentiation. When stratified by cyst type, KRAS had a sensitivity of 67% and 14% for IPMNs and MCNs, respectively. In summary, KRAS mutations were highly specific for mucinous differentiation, but were inadequate in identifying MCNs. Future molecular studies and the combination of other fluid markers are required to improve the detection and classification of pancreatic mucinous neoplasms by endoscopic ultrasound fine-needle aspiration.

Loss of PTEN expression is associated with poor prognosis in patients with intraductal papillary mucinous neoplasms of the pancreas

PURPOSE

Previously, we reported PIK3CA gene mutations in high-grade intraductal papillary mucinous neoplasms (IPMN). However, the contribution of phosphatidylinositol-3 kinase pathway (PI3K) dysregulation to pancreatic carcinogenesis is not fully understood and its prognostic value unknown. We investigated the dysregulation of the PI3K signaling pathway in IPMN and its clinical implication.

EXPERIMENTAL DESIGN

Thirty-six IPMN specimens were examined by novel mutant-enriched sequencing methods for hot-spot mutations in the PIK3CA and AKT1 genes. PIK3CA and AKT1 gene amplifications and loss of heterozygosity at the PTEN locus were also evaluated. In addition, the expression levels of PDPK1/PDK1, PTEN, and Ki67 were analyzed by immunohistochemistry.

RESULTS

Three cases carrying the E17K mutation in the AKT1 gene and one case harboring the H1047R mutation in the PIK3CA gene were detected among the 36 cases. PDK1 was significantly overexpressed in the high-grade IPMN versus low-grade IPMN (P = 0.034) and in pancreatic and intestinal-type of IPMN versus gastric-type of IPMN (P = 0.020). Loss of PTEN expression was strongly associated with presence of invasive carcinoma and poor survival in these IPMN patients (P = 0.014).

CONCLUSION

This is the first report of AKT1 mutations in IPMN. Our data indicate that oncogenic activation of the PI3K pathway can contribute to the progression of IPMN, in particular loss of PTEN expression. This finding suggests the potential employment of PI3K pathway-targeted therapies for IPMN patients. The incorporation of PTEN expression status in making surgical decisions may also benefit IPMN patients and should warrant further investigation.

A review of pancreatic cyst fluid analysis in the differential diagnosis of pancreatic cyst lesions

Diagnosis and management of pancreatic cyst lesions is challenging as there is currently no investigation that offers both high diagnostic sensitivity and high specificity for the identification of potentially malignant lesions. Accurate classification of these lesions is vital in order to avoid unnecessary treatment of benign lesions and missed opportunities for early treatment of lesions that are malignant/pre-malignant. Pancreatic cyst fluid analysis has an important role in diagnosis, although all currently available investigations based on fluid analysis have significant limitations. Cytological analysis can reveal features that are specific for a certain class of cyst, but offers limited sensitivity in detecting malignant/pre-malignant cysts. Measurement of tumour markers, particularly carcinoembryonic antigen can also be informative. Concentrations of cyst fluid carcinoembryonic antigen tend to be higher in malignant/pre-malignant cysts, although there is a wide overlap between the various classes of cyst. A number of studies have suggested that diagnostic carcinoembryonic antigen cut-offs can be chosen that provide a high degree of specificity but limited sensitivity. Studies of the analytical validity of tumour marker assays in pancreatic cyst fluid analysis have highlighted discrepancies in some fluid specimens, which require further investigation. DNA analysis also has a role. In particular, K-Ras-2 mutational analysis appears to provide high specificity for detection of malignant/pre-malignant lesions. A number of diagnostic algorithms have been published, integrating use of available investigations in order to achieve the optimum discrimination of benign and potentially malignant cysts. Research into new biochemical markers and optimal use of available pancreatic cyst fluid analyses is ongoing.

The role of K-ras gene mutation analysis in EUS-guided FNA cytology specimens for the differential diagnosis of pancreatic solid masses: a meta-analysis of prospective studies

BACKGROUND

Differential diagnosis of pancreatic solid masses with EUS-guided FNA (EUS-FNA) is still challenging in about 15% of cases. Mutation of the K-ras gene is present in over 75% of pancreatic adenocarcinomas (PADC).

OBJECTIVE

To assess the accuracy of K-ras gene mutation analysis for diagnosing PADC.

DESIGN

We systematically searched the electronic databases for relevant studies published. Data from selected studies underwent meta-analysis by use of a bivariate model providing a pooled value for sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic curve.

SETTING

Meta-analysis of 8 prospective studies.

PATIENTS

Total of 931 patients undergoing EUS-FNA for diagnosis of pancreatic solid masses.

INTERVENTION

K-ras mutation analysis.

MAIN OUTCOME MEASUREMENTS

Diagnostic accuracy of K-ras mutation analysis and of combined diagnostic strategy by using EUS-FNA and K-ras mutation analysis in the diagnosis of PADC.

RESULTS

The pooled sensitivity of EUS-FNA for the differential diagnosis of PADC was 80.6%, and the specificity was 97%. Estimated sensitivity and specificity were 76.8% and 93.3% for K-ras gene analysis, respectively, and 88.7% and 92% for combined EUS-FNA plus K-ras mutation analysis. Overall, K-ras mutation testing applied to cases that were inconclusive by EUS-FNA reduced the false-negative rate by 55.6%, with a false-positive rate of 10.7%. Not repeating EUS-FNA in cases in which mutation testing of the K-ras gene is inconclusive would reduce the repeat-biopsy rate from 12.5% to 6.8%.

LIMITATIONS

Small number of studies and between-study heterogeneity.

CONCLUSION

K-ras mutation analysis can be useful in the diagnostic work-up of pancreatic masses, in particular when tissue obtained by EUS-FNA is insufficient, and the diagnosis inconclusive.

Pathology and molecular genetics of pancreatic neoplasms

Cancer is fundamentally a genetic disease caused by the accumulation of somatic mutations in oncogenes and tumor suppressor genes. In the last decade, rapid advances in sequencing and bioinformatic technology led to an explosion in sequencing studies of cancer genomes, greatly expanding our knowledge of the genetic changes underlying a variety of tumor types. Several of these studies of cancer genomes have focused on pancreatic neoplasms, and cancers from the pancreas are some of the best characterized tumors at the genetic level. Pancreatic neoplasms encompass a wide array of clinical diseases, from benign cysts to deadly cancers, and the genetic alterations underlying neoplasms of the pancreas are similarly diverse. This new knowledge of pancreatic cancer genomes has deepened our understanding of tumorigenesis in the pancreas and has opened several promising new avenues for novel diagnostics and therapeutics.

MicroRNA from pancreatic duct aspirate differentiates cystic lesions of the pancreas

INTRODUCTION

Prognostication for cystic neoplasms of the pancreas continues to evolve. Beyond simple size and cystic fluid CEA determination, microRNA (miRNA) detection holds great promise as molecular diagnostics for cancer risk. In this study, we sought to identify miRNAs that could predict malignant potential of pancreatic cystic lesions.

METHODS

RNA was harvested from the pancreatic duct aspirate of 72 cystic neoplasms of the pancreas. Samples with adequate RNA concentration (≥ 3 ng/μL) were selected for qRTPCR profiling using assays to 379 of the most common miRNAs. miRNA profiles were correlated with histopathology from resected specimens and grouped by benign (serous cystadenomas), premalignant (intraductal papillary mucinous neoplasms and mucinous cystadenomas), or malignant lesions (adenocarcinoma).

RESULTS

Adequate RNA for analysis was obtained from 42 (58.3 %) of the samples. Malignant lesions were more likely to have adequate RNA (n = 17, 81 %) than either benign (n = 6, 33 %) or premalignant lesions (n = 19, 59 %; p = 0.011). Nine miRNA were identified as differentially expressed between benign and premalignant/malignant lesions (p < 0.05). A significant correlation was found between the number of differentially expressed miRNA and the likelihood of a premalignant/malignant lesion. All premalignant or malignant lesions expressed at least one miRNA surpassing the threshold of mean miRNA expression, whereas no benign lesions had more than one miRNA surpassing the threshold.

CONCLUSIONS

The presence of RNA in the duct aspirate from patients with pancreatic cystic neoplasms may be a predictor of premalignancy or malignancy. miRNA may be utilized to further differentiate between benign, premalignant, and malignant cystic lesions of the pancreas.

Pancreatic cystic neoplasms: management and unanswered questions

Approximately 10% of persons 70 years old or older are now diagnosed with pancreatic cysts, but it is not clear which ones require additional analysis, interventions, or follow-up. Primary care doctors rely on gastroenterologists for direction because no one wants to miss a diagnosis of pancreatic cancer, but meanwhile there is pressure to limit use of diagnostic tests and limit costs. We review the different cystic neoplasms of the pancreas and diagnostic strategies based on clinical features and imaging data. We discuss surgical and nonsurgical management of the most common cystic neoplasms, based on the recently revised Sendai guidelines. Intraductal papillary mucinous neoplasm (particularly the branch duct variant) is the lesion most frequently identified incidentally. We report what is known about its pathology, its risk of developing into pancreatic ductal adenocarcinoma, the pros and cons of current guidelines for management, and the potential role of endoscopic ultrasound in determining cancer risk. We also review surgical treatment and strategies for surveillance of pancreatic cysts.

Correlation of the presence and extent of loss of heterozygosity mutations with histological classifications of Barrett's esophagus

Background

Recent advances in the management of Barrett’s Esophagus (BE) have placed greater emphasis on accurate diagnosis of BE as well as better prediction of risk for progression to esophageal adenocarcinoma (EAC). Histological evaluation of BE is particularly challenging with significant inter-observer variability. We explored the presence and extent of genomic instability in BE biopsy specimens as a means to add supplementary information to the histological classification and clinical decision-making related to early disease.

Methods

We reviewed histology slides from 271 patients known to have BE. Using histological features as a guide, we microdissected target cell populations with various histological classifications of BE (intestinal metaplasia, “indefinite for dysplasia”, low grade dysplasia, or high grade dysplasia). DNA was extracted from microdissected targets and analyzed for loss of heterozygosity (LOH) using a panel of 16 LOH mutational markers associated with tumor suppressor genes at chromosomal loci 1p, 3p, 5q, 9p, 10q, 17p, 17q, 18q, 21q, 22q. The presence or absence of mutations and the clonality of each mutation were determined for each marker.

Results

The presence and clonal expansion of LOH mutations was formulated into mutational load (ML) for each microdissected target analyzed. ML correlated with the histological classification of microdissected targets, with increasingly severe histology having higher ML. Three levels of mutation load (no ML, low ML, and high ML) were defined based on the population of microdissected targets histologically classified as intestinal metaplasia. All microdissected targets with dysplasia had mutations, with a high ML consistently present in high grade dysplasia targets. Microdissected targets histologically classified as intestinal metaplasia or “indefinite for dysplasia” spanned a range of no, low, and high ML.

Conclusions

The results of this study reinforce the association of genomic instability with disease progression in BE. The presence and extent (clonality) of genomic instability, as assessed by mutational load, may assist histology in defining early stages of BE that are potentially at greater risk for disease progression. Assessment of mutational load using our panel of LOH mutational markers may be a useful adjunct to microscopic inspection of biopsy specimens, and thereby, improve patient management.

Commercial molecular panels are of limited utility in the classification of pancreatic cystic lesions

The PathfinderTG biomarker panel is useful in the evaluation of pancreatic cysts that have clinical features suspicious for malignancy, but its utility in classifying fine-needle aspiration biopsies from small pancreatic cystic lesions is yet to be proven. We used morphology to classify 20 pancreatic cyst cytology aspirates, all of which met radiographic criteria for close observation. Cases were cytologically classified as consistent with pseudocyst, serous cystadenoma, or mucinous neoplasm with low-grade, intermediate-grade, or high-grade dysplasia and analyzed for carcinoembryonic antigen. Redpath Integrated Pathology Inc. rendered diagnoses of nonmucinous (reactive/indolent or serous) or mucinous (low-risk or at risk) cyst on the basis of results of the PathfinderTG panel (KRAS mutations, DNA content, and loss of heterozygosity at microsatellites linked to tumor suppressor genes). Cytologic and commercial laboratory diagnoses were concordant in only 7 (35%) cases. Seven cysts classified as mucinous with low-grade dysplasia by cytology were interpreted as nonmucinous on the basis of the PathfinderTG panel, 2 of which were resected mucinous cysts. Two pancreatitis-related pseudocysts were misdiagnosed as low-risk mucinous cysts; 1 mucinous cyst with low-grade dysplasia was considered at risk for neoplastic progression using the PathfinderTG panel. Only 1 cyst misclassified as pseudocyst by cytology, but low-risk mucinous cyst by molecular analysis, proved to be a mucinous cystic neoplasm with low-grade dysplasia after surgical resection. We conclude that the PathfinderTG panel may aid the classification of pancreatic lesions, but is often inaccurate and should not replace cytologic evaluation of these lesions.

Optimizing the multimodal approach to pancreatic cyst fluid diagnosis: developing a volume-based triage protocol

BACKGROUND

The objective of this study was to develop a triage algorithm to optimize diagnostic yield from cytology, carcinoembryonic antigen (CEA), and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) testing on different components of a single pancreatic cyst fluid specimen. The authors also sought to determine whether cell block supernatant was suitable for CEA and KRAS testing.

METHODS

Fifty-four pancreatic cysts were triaged according to a volume-dependent protocol to generate fluid (neat and supernatant) and cell block specimens for cytology, comparative CEA, and KRAS testing. Follow-up histology, diagnostic cytology, or a combined clinicopathologic interpretation was recorded as the final diagnosis.

RESULTS

There were 26 mucinous cystic lesions and 28 nonmucinous cystic lesions with volumes ranging from 0.3 mL to 55 mL. Testing different components of the specimens (cell block, neat, and/or supernatant) enabled all laboratory investigations to be performed on 50 of 54 cyst fluids (92.6%). Interpretive concordance was observed in 17 of 17 cases (100%) and in 35 of 40 cases (87.5%) that had multiple components tested for CEA and KRAS mutations, respectively. An elevated CEA level (>192 ng/mL) was the most sensitive test for the detection of a mucinous cystic lesion (62.5%) versus KRAS mutation (56%) and "positive" cytology (61.5%). KRAS mutations were identified in 2 of 25 mucinous cystic lesions (8%) in which cytology and CEA levels were not contributory.

CONCLUSIONS

A volume-based protocol using different components of the specimen was able to optimize diagnostic yield in pancreatic cyst fluids. KRAS mutation testing increased diagnostic yield when combined with cytology and CEA analysis. The current results demonstrated that supernatant is comparable to neat fluid and cell block material for CEA and KRAS testing.

PAM4 enzyme immunoassay alone and in combination with CA 19-9 for the detection of pancreatic adenocarcinoma

BACKGROUND

The monoclonal antibody PAM4 has high specificity for pancreatic ductal adenocarcinoma (PDAC), as well as its precursor lesions, but has not been found to be reactive with normal and benign pancreatic tissues. The objective of the current study was to evaluate a PAM4-based serum enzyme immunoassay alone and in combination with the carbohydrate antigen (CA) 19-9 assay for the detection of PDAC, with particular attention to early stage disease.

METHODS

Sera from patients with confirmed PDAC (N = 298), other cancers (N = 99), benign disease of the pancreas (N = 120), and healthy adults (N = 79) were evaluated by a specific enzyme immunoassay for the concentration of PAM4 and CA 19-9 antigen levels by blinded analyses. All tests for statistical significance were 2-sided.

RESULTS

The overall sensitivity for PAM4 detection of PDAC was 76%, with 64% of patients with stage I disease also identified. The detection rate was considerably higher (85%) for patients with advanced disease. The assay demonstrated high specificity compared with benign pancreatic disease (85%), with a positive likelihood ratio of 4.93. CA 19-9 provided an overall sensitivity of 77%, and was positive in 58% of patients with stage I disease; however, the specificity was significantly lower for CA 19-9 (68%), with a positive likelihood ratio of 2.85 (P = .026 compared with PAM4). It is important to note that a combined PAM4 and CA 19-9 biomarker serum assay demonstrated an improved sensitivity (84%) for the overall detection of PDAC without a significant loss of specificity (82%) compared with either arm alone.

CONCLUSIONS

The PAM4 enzyme immunoassay identified approximately two-thirds of patients with stage I PDAC with high discriminatory power with respect to benign, nonneoplastic pancreatic disease. These results provide a rationale for testing patient groups considered to be at high risk for PDAC with a combined PAM4 and CA 19-9 biomarker serum assay for the detection of early stage PDAC.

Molecular analysis of cyst fluid aspiration in the diagnosis and risk assessment of cystic lesions of the pancreas

Pancreatic cyst detection is increasing largely due to increasing use of cross-sectional imaging. The management of pancreatic cysts differs for true cysts, pseudocysts, mucinous cysts, nonmucinous cysts, and malignant lesions. Depending on the setting, diagnostic tests, such as cross-sectional imaging, endoscopic ultrasound, cyst fluid chemistry, and cytology, have moderate accuracy in characterizing the cyst subtype. Molecular analysis of cyst fluid aspirates has shown promise in preliminary studies and may require smaller fluid volumes than is needed for carcinoembryonic antigen level and cytology. This article reviews published studies in which molecular analysis was performed in the evaluation of pancreatic cysts. The molecular studies are compared with the conventional tests. Most studies have had moderate sample sizes (16-124) and have characterized a high proportion of patients with malignant cysts. Evaluation of molecular analysis as a diagnostic tool merits larger prospective trials with long-term follow-up of patients who are not sent to surgery. Larger cysts may meet size criteria for resection, and it is the smaller cysts for which molecular analysis may be of benefit if additional molecular testing results in a change in management.

Detection of KRAS gene mutations in endoscopic ultrasound-guided fine-needle aspiration biopsy for improving pancreatic cancer diagnosis

OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is a useful tool in the diagnosis of pancreatic masses. Genetic analysis of these samples could increase the sensitivity and specificity of diagnosis. This study aimed to evaluate the usefulness of a novel method for the detection of mutations in the KRAS (Kirsten rat sarcoma-2 virus) gene for the diagnosis of pancreatic cancer.

METHODS

EUS-FNABs were performed on 82 patients with pancreatic masses, including 54 cases of pancreatic ductal adenocarcinoma and 28 of non-malignant pancreatic masses. The biopsies were histopathologically and cytopathologically evaluated, and the detection of KRAS gene mutations (codons 12 and 13) was performed through peptide nucleic acid-directed polymerase chain reaction clamping and DNA sequencing.

RESULTS

In the pancreatic cancer cases, 88.9% (48/54; 95% confidence interval (CI): 80.5-97.2%) had KRAS mutations, while 61.1% (33/54; 95% CI: 48.1-74.1%) were unequivocally diagnosed by histo/cytopathology. In the indeterminate patients (n=49; diagnosed by EUS-FNA as either insufficient material to make a diagnosis, no malignancy, or suspicion of malignancy), there were 10 cases of pancreatic cancer with low serum carbohydrate antigen 19-9 (CA19-9) (<37 U/l) and 6 of these were KRAS mutations. The sensitivity of detection by KRAS mutations (76.2%) and the combination of KRAS mutations and serum CA19-9 (81%) were significantly higher than for serum CA19-9 alone (52.4%). A logistic regression model showed that the KRAS mutation was significant (odds ratio=5.830; CI: 1.531-22.199, P=0.01), but not serum CA19-9. In the non-malignant pancreatic masses (n=28), KRAS mutations were detected in nine precancerous lesions.

CONCLUSIONS

Our method for the detection of KRAS gene mutations may be useful to supplement histo/cytopathologic evaluations for pancreatic cancer, and is superior to serum CA19-9 in EUS-FNAB histo/cytopathology-indeterminate patients. Results warrant further verification in other patient populations.