Endoscopic ultrasound-guided fine-needle aspiration biopsy coupled with KRAS mutation assay to distinguish pancreatic cancer from pseudotumoral chronic pancreatitis

K-ras gene mutation analysis to diagnosis pancreatic adenocarcinoma from endoscopic ultrasound-guided tissue acquisition; a systematic review and meta-analysis

BACKGROUND

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) has high sensitivity for the pathological diagnosis of pancreatic masses, but also a high false-negative rate. K-ras gene mutations occur in over 75 % of pancreatic ductal adenocarcinomas (PDAC), and this meta-analysis evaluated the utility of detecting K-ras gene mutations from EUS-TA specimens for the diagnosis of PDAC.

METHODS

Relevant studies in PubMed, the Cochrane Library, and Web of Science were systematically searched. Meta-analysis was performed on data from the selected studies using a bivariate model to provide pooled values of sensitivity, specificity, and their 95 % confidence intervals (CIs).

RESULTS

This meta-analysis included 1521 patients (from 10 eligible studies) who underwent EUS-TA with K-ras gene mutation analysis for diagnosis of pancreatic solid masses. The pooled estimates of sensitivity and specificity were 76.6 % (95 % CI, 70.9-81.5 %) and 97.0 % (95 % CI, 94.0-98.5 %), respectively, for pathological diagnosis, 75.9 % (95 % CI 69.5-81.4 %) and 95.3 % (95 % CI, 92.3-97.2 %) for K-ras gene mutation analysis, and 88.7 % (95 % CI 87.1-91.7 %) and 94.9 % (95 % CI, 91.5-97.0 %) for pathological diagnosis in combination with K-ras gene mutation analysis. The sensitivity for diagnosis of PDAC was significantly higher for pathological diagnosis in combination with K-ras gene mutation analysis than for pathological diagnosis or K-ras gene mutation analysis alone (both, p < 0.001). There was no difference in specificity between pathological diagnosis in combination with K-ras gene mutation analysis and both either (p = 0.234, 0.945, respectively).

CONCLUSIONS

K-ras gene mutation analysis in combination with to pathological diagnosis of EUS-TA increases the accuracy of differential diagnosis of PDAC.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

Background

The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB).

Objectives

We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival.

Design

In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed.

Methods

The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC).

Results

A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation.

Conclusion

KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

The Latest Advancements in Diagnostic Role of Endosonography of Pancreatic Lesions

Endosonography, a minimally invasive imaging technique, has revolutionized the diagnosis and management of pancreatic diseases. This comprehensive review highlights the latest advancements in endosonography of the pancreas, focusing on key technological developments, procedural techniques, clinical applications and additional techniques, which include real-time elastography endoscopic ultrasound, contrast-enhanced-EUS, EUS-guided fine-needle aspiration or EUS-guided fine-needle biopsy. EUS is well established for T-staging and N-staging of pancreaticobiliary malignancies, for pancreatic cyst discovery, for identifying subepithelial lesions (SEL), for differentiation of benign pancreaticobiliary disorders or for acquisition of tissue by EUS-guided fine-needle aspiration or EUS-guided fine-needle biopsy. This review briefly describes principles and application of EUS and its related techniques.

Combining the amplification refractory mutation system and high-resolution melting analysis for KRAS mutation detection in clinical samples

The success of personalized medicine depends on the discovery of biomarkers that allow oncologists to identify patients that will benefit from a particular targeted drug. Molecular tests are mostly performed using tumor samples, which may not be representative of the tumor's temporal and spatial heterogeneity. Liquid biopsies, and particularly the analysis of circulating tumor DNA, are emerging as an interesting means for diagnosis, prognosis, and predictive biomarker discovery. In this study, the amplification refractory mutation system (ARMS) coupled with high-resolution melting analysis (HRMA) was developed for detecting two of the most relevant KRAS mutations in codon 12. After optimization with commercial cancer cell lines, KRAS mutation screening was validated in tumor and plasma samples collected from patients with pancreatic ductal adenocarcinoma (PDAC), and the results were compared to those obtained by Sanger sequencing (SS) and droplet digital polymerase chain reaction (ddPCR). The developed ARMS-HRMA methodology stands out for its simplicity and reduced time to result when compared to both SS and ddPCR but showing high sensitivity and specificity for the detection of mutations in tumor and plasma samples. In fact, ARMS-HRMA scored 3 more mutations compared to SS (tumor samples T6, T7, and T12) and one more compared to ddPCR (tumor sample T7) in DNA extracted from tumors. For ctDNA from plasma samples, insufficient genetic material prevented the screening of all samples. Still, ARMS-HRMA allowed for scoring more mutations in comparison to SS and 1 more mutation in comparison to ddPCR (plasma sample P7). We propose that ARMS-HRMA might be used as a sensitive, specific, and simple method for the screening of low-level mutations in liquid biopsies, suitable for improving diagnosis and prognosis schemes.

Approach to Pancreatic Head Mass in the Background of Chronic Pancreatitis

Chronic pancreatitis (CP) is a known risk factor for pancreatic cancer. CP may present with an inflammatory mass, and differentiation from pancreatic cancer is often difficult. Clinical suspicion of malignancy dictates a need for further evaluation for underlying pancreatic cancer. Imaging modalities remain the mainstay of evaluation for a mass in background CP; however, they have their shortcomings. Endoscopic ultrasound (EUS) has become the go-to investigation. Adjunct modalities such as contrast-harmonic EUS and EUS elastography, as well as EUS-guided sampling using newer-generation needles are useful in differentiating inflammatory from malignant masses in the pancreas. Paraduodenal pancreatitis and autoimmune pancreatitis often masquerade as pancreatic cancer. In this narrative review, we discuss the various modalities used to differentiate inflammatory from malignant masses of the pancreas.

Pancreatic Cancer in Chronic Pancreatitis: Pathogenesis and Diagnostic Approach

Chronic pancreatitis is one of the main risk factors for pancreatic cancer, but it is a rare event. Inflammation and oncogenes work hand in hand as key promoters of this disease. Tobacco is another co-factor. During alcoholic chronic pancreatitis, the cumulative risk of cancer is estimated at 4% after 15 to 20 years. This cumulative risk is higher in hereditary pancreatitis: 19 and 12% in the case of PRSS1 and SPINK1 mutations, respectively, at an age of 60 years. The diagnosis is difficult due to: (i) clinical symptoms of cancer shared with those of chronic pancreatitis; (ii) the parenchymal and ductal remodeling of chronic pancreatitis rendering imaging analysis difficult; and (iii) differential diagnoses, such as pseudo-tumorous chronic pancreatitis and paraduodenal pancreatitis. Nevertheless, the occurrence of cancer during chronic pancreatitis must be suspected in the case of back pain, weight loss, unbalanced diabetes, and jaundice, despite alcohol withdrawal. Imaging must be systematically reviewed. Endoscopic ultrasound-guided fine-needle biopsy can contribute by targeting suspicious tissue areas with the help of molecular biology (search for KRAS, TP53, CDKN2A, DPC4 mutations). Short-term follow-up of patients is necessary at the clinical and paraclinical levels to try to diagnose cancer at a surgically curable stage. Pancreatic surgery is sometimes necessary if there is any doubt.

Diagnostic and Prognostic Values of KRAS Mutations on EUS-FNA Specimens and Circulating Tumor DNA in Patients With Pancreatic Cancer

INTRODUCTION

The ability of carbohydrate antigen 19-9 (CA19-9) to differentiate pancreatic cancer from other benign pancreatic lesions is unsatisfactory. This study explored the diagnostic value of KRAS gene mutations and plasma circulating tumor DNA (ctDNA) in patients with pancreatic cancer.

METHODS

The prospective cohort study comprised 149 consecutive patients with solid pancreatic lesions who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). KRAS subtype mutations were analyzed by digital droplet PCR (ddPCR) in EUS-FNA histopathology tissue samples, and blood samples were sent for plasma ctDNA analysis. The final diagnosis was based on surgical resection pathology or follow-up for at least 2 years.

RESULTS

Adding KRAS mutation ddPCR increased the sensitivity and accuracy of EUS-FNA from 71.4% to 91.6% (P < 0.001) and 75.8% to 88.6% (P < 0.001), respectively. By comparison, the sensitivities of circulating biomarkers ctDNA and CA19-9 were only 35.2% and 71.2%. The area under the curve of the receiver operating characteristic curve (AUC) of EUS-FNA and KRAS ddPCR combination was >0.90 for distinguishing pancreatic cancer from benign lesions, whereas the AUC of EUS-FNA and CA19-9 combination was 0.83. The median survival time was significantly shorter in patients with G12D KRAS mutations than that in patients with other mutations (180 vs 240 days, P < 0.001).

DISCUSSION

FNA tissue sample KRAS mutation analysis in tissues significantly improves the diagnostic accuracy of cyto/histopathological evaluation in EUS-FNA samples. The combination of EUS-FNA and tissue sample KRAS ddPCR provided a more accurate method for pancreatic cancer diagnosis, superior to the combination of EUS-FNA and CA19-9/ctDNA. G12D KRAS mutations in pancreatic cancer were independently associated with poor overall survival.

Pancreatic Cancer-Related Mutational Burden Is Not Increased in a Patient Cohort With Clinically Severe Chronic Pancreatitis

INTRODUCTION

Chronic pancreatitis is associated with an increased risk of developing pancreatic cancer, and patients with inherited forms of pancreatitis are at greatest risk. We investigated whether clinical severity of pancreatitis could also be an indicator of cancer risk independent of etiology by performing targeted DNA sequencing to assess the mutational burden in 55 cancer-associated genes.

METHODS

Using picodroplet digital polymerase chain reaction and next-generation sequencing, we reported the genomic profiles of pancreases from severe clinical cases of chronic pancreatitis that necessitated palliative total pancreatectomy with islet autotransplantation.

RESULTS

We assessed 57 tissue samples from 39 patients with genetic and idiopathic etiologies and found that despite the clinical severity of disease, there was no corresponding increase in mutational burden. The average allele frequency of somatic variants was 1.19% (range 1.00%-5.97%), and distinct regions from the same patient displayed genomic heterogeneity, suggesting that these variants are subclonal. Few oncogenic KRAS mutations were discovered (7% of all samples), although we detected evidence of frequent cancer-related variants in other genes such as TP53, CDKN2A, and SMAD4. Of note, tissue samples with oncogenic KRAS mutations and samples from patients with PRSS1 mutations harbored an increased total number of somatic variants, suggesting that these patients may have increased genomic instability and could be at an increased risk of developing pancreatic cancer.

DISCUSSION

Overall, we showed that even in those patients with chronic pancreatitis severe enough to warrant total pancreatectomy with islet autotransplantation, pancreatic cancer-related mutational burden is not appreciably increased.

Molecular alterations in pancreatic tumors

Genetic alterations in pancreatic tumors can usually be classified in: (1) Mutational activation of oncogenes; (2) Inactivation of tumor suppressor genes; and (3) Inactivation of genome maintenance genes controlling the repair of DNA damage. Endoscopic ultrasound-guided fine-needle aspiration has improved pre-operative diagnosis, but the management of patients with a pancreatic lesion is still challenging. Molecular testing could help mainly in solving these “inconclusive” specimens. The introduction of multi-gene analysis approaches, such as next-generation sequencing, has provided a lot of useful information on the molecular characterization of pancreatic tumors. Different types of pancreatic tumors (e.g., pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, solid pseudopapillary tumors) are characterized by specific molecular alterations. The aim of this review is to summarize the main molecular alterations found in pancreatic tumors.

Features of chronic pancreatitis by endoscopic ultrasound influence the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration of small pancreatic lesions

BACKGROUND AND AIM

In chronic pancreatitis (CP) patients, diagnosis of small pancreatic lesions by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is challenging. Thus, the aim of the present study was to investigate whether CP influences the diagnostic ability of EUS-FNA for pancreatic lesions ≤10 mm.

METHODS

One hundred and seventeen patients who underwent EUS-FNA for pancreatic lesions ≤10 mm in size were enrolled. Patients were classified into two groups based on features of CP observed by EUS (EUS-CP features) in accordance with the Rosemont classification. The CP group was defined as cases consistent with CP or suggestive of CP, and the non-CP group was defined as cases indeterminate for CP or normal. Factors influencing the diagnostic accuracy of EUS-FNA and CP status in pancreatic tumors were also investigated.

RESULTS

Diagnostic ability of EUS-FNA (overall cases, non-CP vs CP) had sensitivity (80.4%, 96.7% vs 57.1%; P < 0.001), specificity (100%, 100% vs 100%; P > 0.05), and accuracy (91.5%, 98.6% vs 80.4%; P = 0.001). In multivariate analysis of factors influencing the accuracy of EUS-FNA, CP significantly lowered the accuracy (P = 0.048; odds ratio [OR] = 9.21). Among pancreatic cancer patients, the number of CP patients was significantly higher than the number of patients with benign lesions (P = 0.023). In multivariate analysis, lobularity without honeycombing was more frequently observed in cases of pancreatic cancer (P = 0.018; OR, 12.65).

CONCLUSION

Endoscopic ultrasound-guided FNA offers high accuracy for small pancreatic lesions ≤10 mm. However, in cases with CP, the diagnostic ability of EUS-FNA is significantly reduced.

Role of oncogenic KRAS in the diagnosis, prognosis and treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second most common cause of death within the next 10 years. The prognosis for this disease is poor despite diagnostic progress and new chemotherapeutic regimens. The oncogenic KRAS mutation is the major event in pancreatic cancer; it confers permanent activation of the KRAS protein, which acts as a molecular switch to activate various intracellular signalling pathways and transcription factors inducing cell proliferation, migration, transformation and survival. Several laboratory methods have been developed to detect KRAS mutations in biological samples, including digital droplet PCR (which displays high sensitivity). Clinical studies have revealed that a KRAS mutation assay in fine-needle aspiration material combined with cytopathology increases the sensitivity, accuracy and negative predictive value of cytopathology for a positive diagnosis of pancreatic cancer. In addition, the presence of KRAS mutations in serum and plasma (liquid biopsies) correlates with a worse prognosis. The presence of mutated KRAS can also have therapeutic implications, whether at the gene level per se, during its post-translational maturation, interaction with nucleotides and after activation of the various oncogenic signals. Further pharmacokinetic and toxicological studies on new molecules are required, especially small synthetic molecules, before they can be used in the therapeutic arsenal for pancreatic ductal adenocarcinoma.

New Era of Endoscopic Ultrasound-Guided Tissue Acquisition: Next-Generation Sequencing by Endoscopic Ultrasound-Guided Sampling for Pancreatic Cancer

Pancreatic cancer is a lethal cancer with an increasing incidence. Despite improvements in chemotherapy, patients with pancreatic cancer continue to face poor prognoses. Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is the primary method for obtaining tissue samples of pancreatic cancer. Due to advancements in next-generation sequencing (NGS) technologies, multiple parallel sequencing can be applied to EUS-TA samples. Genomic biomarkers for therapeutic stratification in pancreatic cancer are still lacking, however, NGS can unveil potential predictive genomic biomarkers of treatment response. Thus, the importance of NGS using EUS-TA samples is becoming recognized. In this review, we discuss the recent advances in EUS-TA application for NGS of pancreatic cancer.

Analysis of BRCAness with multiplex ligation-dependent probe amplification using formalin-fixed and paraffin-embedded pancreatic ductal adenocarcinoma tissue obtained via endoscopic ultrasound-guided fine-needle aspiration biopsy

BACKGROUND/OBJECTIVES

A breakthrough in chemotherapy for pancreatic ductal adenocarcinoma (PDAC) may be achieved using precision medicine, which involves identifying cases that are highly likely to respond to a certain treatment and then performing that treatment. BRCAness has been receiving attention as a novel predictor of anticancer drug sensitivity in PDAC, making the screening of BRCAness paramount.

METHODS

We conducted the first-ever examination of the feasibility of analyzing BRCAness using multiplex ligation-dependent probe amplification (MLPA). Formalin-fixed paraffin-embedded (FFPE) tissue samples obtained via endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) from 20 patients with the highest pancreatic carcinoma cell counts in tissue samples out of 40 consecutive PDAC patients who underwent EUS-FNAB at our hospital were analyzed by MLPA for BRCAness.

RESULTS

We were able to accurately analyze BRCAness in 75% of the 20 cases of PDAC using FFPE tissue obtained by EUS-FNAB. BRCAness was observed in one of the 20 cases.

CONCLUSIONS

In PDAC, analyzing BRCAness by MLPA using FFPE tissue obtained by EUS-FNAB offers the remarkable benefit of yielding results in a short period of time and at a low cost. In addition, this method of BRCAness analysis may prove to be a feasible and effective approach for performing precision medicine.

A prospective clinical and biological database for pancreatic adenocarcinoma: the BACAP cohort

BACKGROUND

The prognosis for pancreatic cancer remains poor despite diagnostic advances and treatments with new chemotherapeutic regimens. The five year survival rate remains below 3%. Consequently, there is an urgent need for new treatments to significantly improve the prognosis. In addition, there is a big gap in terms of the screening, early diagnosis and prevention of pancreatic cancer the incidence of which is increasing dramatically.

METHODS

Design: the BACAP cohort is a prospective multicenter pancreatic cancer cohort (pancreatic ductal carcinoma) with clinical and multiple biological samples; Participating centers: 15 French academic and private hospitals; Study Population: any cytologically and/or histologically proven pancreatic carcinoma regardless of the stage (resectable, borderline, locally advanced or metastatic) or treatment (surgery, palliative chemotherapy, best supportive care). At least 1500 patients will be included. Clinical data collected include: disease presentation, epidemiological and social factors, baseline biology, radiology, endoscopic ultrasound, staging, pathology, treatments, follow-up (including biological and radiological), and survival. All these data are collected and stored through an e-observation system at a centralized data center. Biological samples and derived products (i.e. before any treatment): blood, saliva, endoscopic ultrasound-guided fine needle aspiration materials from the primary tumor, fine needle biopsy of metastases and surgically resected tissue. DNA and RNA are extracted from fine needle aspiration materials and are quantified and characterized for quality. Whole blood, plasma and serum are isolated from blood samples. Frozen tissues were specifically allocated to the cohort. All derived products and saliva are stored at - 80 °C. Main end-points: i) to centralize clinical data together with multiple biological samples that are harmonized in terms of sampling, the post sampling process and storage; ii) to identify new molecular markers for the diagnosis, prognosis and possibly the predictive response to pancreatic cancer surgery and or chemotherapy.

DISCUSSION

The BACAP cohort is a unique prospective biological clinical database that provides the opportunity to identify correlations between the presence/expression of a broad panel of biomarkers (DNA, RNA, miRNA, proteins, etc.), epidemiological and social data, various clinical situations, various stages and the differentiation of the tumor, treatments and survival.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02818829 . Registration date: June 30, 2016.

A quarter century of EUS-FNA: Progress, milestones, and future directions

Tissue acquisition using EUS has considerably evolved since the first EUS-FNA was reported 25 years ago. Its introduction was an important breakthrough in the endoscopic field. EUS-FNA has now become a part of the diagnostic and staging algorithm for the evaluation of benign and malignant diseases of the gastrointestinal tract and of the organs in its proximity, including lung diseases. This review aims to present the history of EUS-FNA development and to provide a perspective on the recent developments in procedural techniques and needle technologies that have significantly extended the role of EUS and its clinical applications. There is a bright future ahead for EUS-FNA in the years to come as extensive research is conducted in this field and various technologies are continuously implemented into clinical practice.

K-ras mutation analysis of residual liquid-based cytology specimens from endoscopic ultrasound-guided fine needle aspiration improves cell block diagnosis of pancreatic ductal adenocarcinoma

Background

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) technology is widely used for the diagnosis of pancreatic masses. However, in some cases, inadequate tissue volume or difficulty of morphological diagnosis are constraining factors for adequate cytopathological evaluation. K-ras mutation is the most frequently acquired genetic abnormality, occurring in approximately 90% of all patients with pancreatic ductal adenocarcinoma (PDAC). In the present study, the clinical utility of residual liquid-based cytology (LBC) specimens obtained using EUS-FNA for K-ras mutation analysis was evaluated.

Methods

In this study, 81 patients with pancreatic lesions were examined. The cell block (CB) specimens separated from EUS-FNA samples were morphologically evaluated by hematoxylin–eosin (HE) staining. Final diagnoses were confirmed by CB specimens, surgical resection specimens, diagnostic imaging, and clinical follow-up. Genomic DNA of residual LBC specimens stored at 4°C for several months were extracted and assessed for K-ras mutations using a fluorescence resonance energy transfer-based preferential homoduplex formation assay.

Results

K-ras mutation analysis using residual LBC samples was successful in all cases. The sensitivity, specificity, and accuracy of CB examination alone were 77.4%, 100%, and 81.3%, respectively, and those of the combination of CB examination and K-ras mutation analysis were 90.3%, 92.3%, and 90.7%, respectively. Furthermore, K-ras mutations were detected in 8 (57.1%) of 14 PDAC samples for which the CB results were inconclusive.

Conclusion

These findings suggest that K-ras mutation analysis using residual LBC specimens improves the diagnostic accuracy of EUS-FNA.

Reviewing the Utility of EUS FNA to Advance Precision Medicine in Pancreatic Cancer

Advanced pancreatic cancer (PC) is an aggressive malignancy with few effective therapeutic options. While the evolution of precision medicine in recent decades has changed the treatment landscape in many cancers, at present no targeted therapies are used in the routine management of PC. Only a minority of patients with PC present with surgically resectable disease, and in the remainder obtaining high quality biopsy material for both diagnosis and molecular testing can prove challenging. Endoscopic ultrasound-guided fine needle aspiration (EUS FNA) is a widely used diagnostic procedure in PC, and allows tumour sampling in patients with both early and late stage disease. This review will provide an update on the role of EUS FNA as a diagnostic tool, as well as a source of genetic material which can be used both for molecular analysis and for the creation of valuable preclinical disease models. We will also consider relevant clinical applications of EUS FNA in the management of PC, and the path towards bringing precision medicine closer to the clinic in this challenging disease.

FNA smears of pancreatic ductal adenocarcinoma are superior to formalin-fixed paraffin-embedded tissue as a source of DNA: Comparison of targeted KRAS amplification and genotyping in matched preresection and postresection samples

BACKGROUND

The current study was conducted to compare DNA yield, including normalization to nuclear area, DNA amplification functionality, and detection of KRAS mutations between matched fine-needle aspiration (FNA) specimens and pancreatic resections diagnostic of pancreatic ductal adenocarcinoma.

METHODS

A retrospective sample of 30 matched single FNA smears and macrodissected formalin-fixed, paraffin-embedded (FFPE) curls (2 5-μm curls) were compared by measuring the following: nuclear area (via digital image analysis), DNA yield (via NanoDrop spectrophotometry and Quantus fluorometry), and polymerase chain reaction threshold cycles for KRAS amplifications. Variants in KRAS codons 12/13 and 61 were detected by fluorescent melt curve analyses, followed by Sanger DNA sequencing.

RESULTS

Despite a similar nuclear area, FNA smears yielded greater DNA per nuclear area via 2 DNA quantification methods. KRAS codon 12 mutations were detected in 23 of 30 FNA specimens (77%) compared with 17 of 30 matched FFPE specimens (57%), for a concordance rate of 74%. No KRAS codon 13 or 61 mutations were detected.

CONCLUSIONS

FNA specimens are a more optimal source of DNA, and represent an important resource in the preresection and postresection molecular analysis of pancreatic ductal adenocarcinoma. Cancer Cytopathol 2017;125:838-47. © 2017 American Cancer Society.

Endoscopic Ultrasonography with Fine-needle Aspiration: New Techniques for Interpretation of Endoscopic Ultrasonography Cytology and Histology Specimens

Significant advances have been made in the last few years in the technologies for sampling pancreatic masses, and in the understanding of the biology of pancreatic cancer. Better and more targeted treatments are likely to become available. Because most pancreatic cancers are likely to remain unresectable at diagnosis, high-quality, high-cellularity specimens are essential. A tailored approach that considers indication, location, and treatment possibilities needs to be taken before embarking on a pancreatic biopsy. Because the demand from oncologists and patients for increasingly personalized therapy is likely to grow, optimal sampling beyond diagnostic accuracy is likely to become increasingly critical.

Team work and cytopathology molecular diagnosis of solid pancreatic lesions

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of cancer-associated death in the next decade or so. It is widely accepted that tumorigenesis is linked to specific alterations in key genes and pancreatic neoplasms are some of the best characterized at the genomic level. Recent whole-exome and whole-genome sequencing analyses confirmed that PDAC is frequently characterized by mutations in a set of four genes among others: KRAS, TP53, CDKN2A/p16, and SMAD4. Sequencing, for example, is the preferable technique available for detecting KRAS mutations, whereas in situ immunochemistry is the main approach for detecting TP53 gene alteration. Nevertheless, the diagnosis of PDAC is still a clinical challenge, involving adequate acquisition of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) and specific pathological assessment from tissue architecture to specific biomolecular tests. The aim of the present review is to provide a complete overview of the current knowledge of the biology of pancreatic cancer as detected by the latest biomolecular techniques and, moreover, to propose a paradigm for strict teamwork collaboration in order to improve the correct use of diagnostic sources.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Additional K-ras mutation analysis and Plectin-1 staining improve the diagnostic accuracy of pancreatic solid mass in EUS-guided fine needle aspiration

Background

One of the major genetic alterations in pancreatic ductal adenocarcinoma (PDAC) is the point mutation of K-ras gene. Plectin-1 was also recently identified as PDAC specific biomarker. The aim of this study was to investigate the improvement of diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) by using additional K-ras mutation analysis and Plectin-1 staining in patients with pancreatic mass.

Methods

A total of 85 study patients with pancreatic mass underwent EUS-FNA and the final diagnoses were as follows; PDACs: 70 patients, pancreas neuroendocrine tumor: 4, metastasis to pancreas: 5, autoimmune pancreatitis: 3, chronic pancreatitis: 1, tuberculous lymphadenitis: 1, pseudocyst: 1.

Results

Sensitivity, specificity and accuracy of pathologic diagnosis in EUS-FNA specimen were 81%, 80% and 79% accordingly. When we combine K-ras gene mutation analysis with histological assessment, we could get the following results for sensitivity, specificity and accuracy; cytology and K-ras mutation analysis: 93%, 87%, and 92%, cytology, K-ras mutation analysis, and Plectin-1 staining: 96%, 93%, and 95%.

Conclusions

Triple combinations of the techniques; cytology, K-ras gene mutation analysis, Plectin-1 staining could increase accuracy in diagnosis of PDACs. Further investigation of using minimal specimens from EUS-FNA may give us insight to understand the biological behavior of PDAC.

Endoscopic ultrasound-guided fine-needle aspiration plus KRAS and GNAS mutation in malignant intraductal papillary mucinous neoplasm of the pancreas

Background:KRAS and GNAS mutations are common in intraductal papillary mucinous neoplasia of the pancreas (IPMN). The aims of this study were to assess the role of pre-therapeutic cytopathology combined with KRAS and GNAS mutation assays within cystic fluid sampled by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) to predict malignancy of IPMN. Patients and methods: We prospectively included 37 IPMN patients with clinical and/or imaging predictors of malignancy (men: 24; mean age: 69.5 years). Cytopathology (performed on cystic fluid and/or IPMN nodules), KRAS (Exon 2, codon 12) and GNAS (Exon 8, codon 201) mutations assays (using TaqMan^® allelic discrimination) were performed on EUS-FNA material. The final diagnosis was obtained from IPMN resections (n = 18); surgical biopsies, EUS-FNA analyses, and follow-up (n = 19): 10 and 27 IPMN were benign and malignant, respectively. Results: Sensitivity, specificity, positive and negative predictive values, and accuracy of cytopathology alone to diagnose IPMN malignancy were 55 %, 100 %, 100 %, 45 %, and 66 %, respectively. When KRAS-mutation analysis was combined with cytopathology these values were 92 %, 50 %, 83 %, 71 %, and 81 %, respectively. GNAS assays did not improve the performances of cytopathology alone or those of cytopathology plus a KRAS assay. Conclusions: In patients with a likelihood of malignant IPMN at pre-therapeutic investigation, testing for KRAS mutations in cystic fluid sampling by EUS-FNA improved the results of cytopathology for the diagnosis of malignancy whereas GNAS mutation assay did not.

Targeted next generation sequencing of endoscopic ultrasound acquired cytology from ampullary and pancreatic adenocarcinoma has the potential to aid patient stratification for optimal therapy selection

BACKGROUND & AIMS

Less than 10% of registered drug intervention trials for pancreatic ductal adenocarcinoma (PDAC) include a biomarker stratification strategy. The ability to identify distinct mutation subsets via endoscopic ultrasound fine needle aspiration (EUS FNA) molecular cytology could greatly aid clinical trial patient stratification and offer predictive markers. We identified chemotherapy treatment naïve ampullary adenocarcinoma and PDAC patients who underwent EUS FNA to assess multigene mutational frequency and diversity with a surgical resection concordance assessment, where available.

METHODS

Following strict cytology smear screening criteria, targeted next generation sequencing (NGS) using a 160 cancer gene panel was performed.

RESULTS

Complete sequencing was achieved in 29 patients, whereby 83 pathogenic alterations were identified in 21 genes. Cytology genotyping revealed that the majority of mutations were identified in KRAS (93%), TP53 (72%), SMAD4 (31%), and GNAS (10%). There was 100% concordance for the following pathogenic alterations: KRAS, TP53, SMAD4, KMT2D, NOTCH2, MSH2, RB1, SMARCA4, PPP2R1A, PIK3R1, SCL7A8, ATM, and FANCD2. Absolute multigene mutational concordance was 83%. Incremental cytology smear mutations in GRIN2A, GATA3 and KDM6A were identified despite re-examination of raw sequence reads in the corresponding resection specimens.

CONCLUSIONS

EUS FNA cytology genotyping using a 160 cancer gene NGS panel revealed a broad spectrum of pathogenic alterations. The fidelity of cytology genotyping to that of paired surgical resection specimens suggests that EUS FNA represents a suitable surrogate and may complement the conventional stratification criteria in decision making for therapies and may guide future biomarker driven therapeutic development.

Fully automated PCR detection of KRAS mutations on pancreatic endoscopic ultrasound fine-needle aspirates

AIMS

In cystic and solid pancreatic lesions, KRAS mutational status refines the diagnosis of uncertain endoscopic ultrasound (EUS) aspirates. This test should have a fast turnaround time and ideally be performed at the centre where the patient is diagnosed. The Idylla KRAS Mutation Test enables standardisation even in units without molecular expertise.

METHODS

The Idylla test was designed for use with formalin-fixed paraffin-embedded (FFPE) sections. However, we directly pipetted 3 µL (corresponding to 1/10th of a DNA preparation from the aspirate sample) in the cartridge, which was automatically run as if an FFPE sample had been inserted. The performance was compared with Sanger sequencing, Allele Specific Locked Nucleic Acid PCR (ASLNAqPCR), and 454 Next Generation Sequencing (454-NGS) in light of clinicopathological end points.

RESULTS

Idylla yielded valid results in 49/52 (94.2%) cases, in 2 h. A total of 18/49 cases showed mutation either in KRAS exon 2 (14/18) or in exon 3 (4/18). Idylla KRAS test had 100% specificity and a sensitivity (55.1%) higher than Sanger sequencing (41.3%) and identical to ASLNAqPCR (55.1%). When the low-abundant mutant allele (<5%) cases were excluded from the analysis, the Idylla KRAS Mutation Test clinical sensitivity increased to 61.9% approaching that of 454-NGS (66.6%).

CONCLUSIONS

This is the first study that applied the novel Idylla KRAS test to the clinical setting of pancreatic cancer. In particular, this system can be easily implemented in the routine assessment of pancreatic EUS-fine-needle aspiration-derived DNA samples to quickly provide information on KRAS mutational status to supplement cytological evaluation.

KRAS G12D Mutation Subtype Is A Prognostic Factor for Advanced Pancreatic Adenocarcinoma

OBJECTIVES

There is no molecular biomarker available in the clinical practice to assess the prognosis of advanced pancreatic carcinoma. This multicenter prospective study aimed to investigate the role of KRAS mutation subtypes within the primary tumor to determine the prognosis of advanced pancreatic cancer.

METHODS

The exon-2 KRAS mutation status was tested on endoscopic ultrasound-guided fine-needle aspiration biopsy material (primary tumor; restriction fragment-length polymorphism plus sequencing and TaqMan allelic discrimination) of patients with proven locally advanced and/or metastatic pancreatic ductal carcinoma. We used the Kaplan-Meier method, log-rank test, and Cox's model to evaluate the impact of KRAS status on the overall survival (OS), adjusting for age, stage of disease, clinical performance status, CA 19-9 levels, and treatment.

RESULTS

A total of 219 patients (men: 116; mean age: 67±9.4 years) were included: 147 harbored a codon-12 KRAS mutation (G12D: 73; G12V: 53; G12R: 21) and 72 had a wild-type KRAS. There was no difference in the OS between patients with a mutant KRAS (8 months; 95% confidence interval (95% CI): 8.7-12.3) and the wild-type (9 months; 95% CI: 8.7-12.8; hazard ratio (HR): 1.03; P=0.82). However, the patients with a G12D mutation had a significantly shorter OS (6 months; 95% CI: 6.4-9.7) compared with the other patients (OS: 9 months; 95% CI: 10-13; HR: 1.47; P=0.003; i.e., wild type: 9 months, G12V: 9 months, G12R: 14 months). Similar results were observed in the subgroup of 162 patients who received chemotherapy (HR: 1.66; P=0.0013; G12D (n=49): 8 months, wild type (n=56): 10 months, G12V (n=38): 10 months, G12R (n=19): 14 months). Multivariate analyses identified KRAS G12D as an independent predictor for worse prognosis within the entire series (HR: 1.44; P=0.01) and in the subgroup of patients that received chemotherapy (HR: 1.84; P=0.02).

CONCLUSIONS

The KRAS G12D mutation subtype is an independent prognostic marker for advanced pancreatic ductal carcinoma. Codon and amino-acid-specific mutations of KRAS should be considered when evaluating the prognoses as well as in trials testing drugs that target RAS and downstream RAS pathways.

Novel Methodology for Rapid Detection of KRAS Mutation Using PNA-LNA Mediated Loop-Mediated Isothermal Amplification

Detecting point mutation of human cancer cells quickly and accurately is gaining in importance for pathological diagnosis and choice of therapeutic approach. In the present study, we present novel methodology, peptide nucleic acid—locked nucleic acid mediated loop-mediated isothermal amplification (PNA-LNA mediated LAMP), for rapid detection of KRAS mutation using advantages of both artificial DNA and LAMP. PNA-LNA mediated LAMP reactions occurred under isothermal temperature conditions of with 4 primary primers set for the target regions on the KRAS gene, clamping PNA probe that was complimentary to the wild type sequence and LNA primers complementary to the mutated sequences. PNA-LNA mediated LAMP was applied for cDNA from 4 kinds of pancreatic carcinoma cell lines with or without KRAS point mutation. The amplified DNA products were verified by naked-eye as well as a real-time PCR equipment. By PNA-LNA mediated LAMP, amplification of wild type KRAS DNA was blocked by clamping PNA probe, whereas, mutant type KRAS DNA was significantly amplified within 50 min. Mutant alleles could be detected in samples which diluted until 0.1% of mutant-to-wild type ratio. On the other hand, mutant alleles could be reproducibly with a mutant-to-wild type ratio of 30% by direct sequencing and of 1% by PNA-clamping PCR. The limit of detection (LOD) of PNA-LNA mediated LAMP was much lower than the other conventional methods. Competition of LNA clamping primers complementary to two different subtypes (G12D and G12V) of mutant KRAS gene indicated different amplification time depend on subtypes of mutant cDNA. PNA-LNA mediated LAMP is a simple, rapid, specific and sensitive methodology for the detection of KRAS mutation.

Diagnostic and therapeutic biomarkers in pancreaticobiliary malignancy

Pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CCA) are two malignancies that carry significant morbidity and mortality. The poor prognoses of these cancers are strongly related to lack of effective screening modalities as well as few therapeutic options. In this review, we highlight novel biomarkers that have the potential to be used as diagnostic, prognostic and predictive markers. The focus of this review is biomarkers that can be evaluated on endoscopically-obtained biopsies or brush specimens in the pre-operative setting. We also provide an overview of novel serum based markers in the early diagnosis of both PDAC and CCA. In pancreatic cancer, the emphasis is placed on prognostic and theranostic markers, whereas in CCA the utility of molecular markers in diagnosis and prognosis are highlighted.

Salivary MicroRNA in Pancreatic Cancer Patients

Background

Pancreatic cancer is the fourth leading cause of cancer death in Western countries, with the lowest 1-year survival rate among commonly diagnosed cancers. Reliable biomarkers for pancreatic cancer diagnosis are lacking and are urgently needed to allow for curative surgery. As microRNA (miRNA) recently emerged as candidate biomarkers for this disease, we explored in the present pilot study the differences in salivary microRNA profiles between patients with pancreatic tumors that are not eligible for surgery, precancerous lesions, inflammatory disease or cancer-free patients as a potential early diagnostic tool.

Methods

Whole saliva samples from patients with pancreatic cancer (n = 7), pancreatitis (n = 4), IPMN (n = 2), or healthy controls (n = 4) were obtained during endoscopic examination. After total RNA isolation, expression of 94 candidate miRNAs was screened by q(RT)PCR using Biomark Fluidgm. Human-derived pancreatic cancer cells were xenografted in athymic mice as an experimental model of pancreatic cancer.

Results

We identified hsa-miR-21, hsa-miR-23a, hsa-miR-23b and miR-29c as being significantly upregulated in saliva of pancreatic cancer patients compared to control, showing sensitivities of 71.4%, 85.7%, 85,7% and 57%, respectively and excellent specificity (100%). Interestingly, hsa-miR-23a and hsa-miR23b are overexpressed in the saliva of patients with pancreatic cancer precursor lesions. We found that hsa-miR-210 and let-7c are overexpressed in the saliva of patients with pancreatitis as compared to the control group, with sensitivity of 100% and 75%, and specificity of 100% and 80%, respectively. Last hsa-miR-216 was upregulated in cancer patients as compared to patients diagnosed with pancreatitis, with sensitivity of 50% and specificity of 100%. In experimental models of PDAC, salivary microRNA detection precedes systemic detection of cancer cells markers.

Conclusions

Our novel findings indicate that salivary miRNA are discriminatory in pancreatic cancer patients that are not eligible for surgery. In addition, we demonstrate in experimental models that salivary miRNA detection precedes systemic detection of cancer cells markers. This study stems for the use of salivary miRNA as biomarker for the early diagnosis of patients with unresectable pancreatic cancer.

Outcomes of nonresected main-duct intraductal papillary mucinous neoplasms of the pancreas

AIM: To compare characteristics and outcomes of resected and nonresected main-duct and mixed intraductal papillary mucinous neoplasms of the pancreas (IPMN).

METHODS: Over a 14-year period, 50 patients who did not undergo surgery for resectable main-duct or mixed IPMN, for reasons of precluding comorbidities, age and/or refusal, were compared with 74 patients who underwent resection to assess differences in rates of survival, recurrence/occurrence of malignancy, and prognostic factors. All study participants had dilatation of the main pancreatic duct by ≥ 5 mm, with or without dilatation of the branch ducts. Some of the nonsurgical patients showed evidence of mucus upon perendoscopic retrograde cholangiopancreatography or endoscopic ultrasound and/or after fine needle aspiration. For the surgical patients, pathologic analysis of resected specimens confirmed a diagnosis of IPMN with involvement of the main pancreatic duct or of both branch ducts as well as the main pancreatic duct. Clinical and biologic follow-ups were conducted for all patients at least annually, through hospitalization or consultation every six months during the first year of follow-up, together with abdominal imaging analysis (magnetic resonance cholangiopancreatography or computed tomography) and, if necessary, endoscopic ultrasound with or without fine needle aspiration.

RESULTS: The overall five-year survival rate of patients who underwent resection was significantly greater than that for the nonsurgical patients (74% vs 58%; P = 0.019). The parameters of age (< 70 years) and absence of a nodule were associated with better survival (P < 0.05); however, the parameters of main pancreatic duct diameter > 10 mm, branch duct diameter > 30 mm, or presence of extra pancreatic cancers did not significantly influence the prognosis. In the nonsurgical patients, pancreatic malignancy occurred in 36% of cases within a mean time of 33 mo (median: 29 mo; range: 8-141 mo). Comparison of the nonsurgical patients who experienced disease progression with those who did not progress showed no significant differences in age, sex, symptoms, subtype of IPMN, or follow-up period; only the size of the main pancreatic duct was significantly different between these two sub-groups, with the nonsurgical patients who experienced progression showing a greater diameter at the time of diagnosis (> 10 mm).

CONCLUSION: Patients unfit for surgery have a 36% greater risk of developing pancreatic malignancy of the main-duct or mixed IPMN within a median of 2.5 years.

Pancreatic cancer early detection: Expanding higher-risk group with clinical and metabolomics parameters

Pancreatic ductal adenocarcinoma (PDAC) is the fourth and fifth leading cause of cancer death for each gender in developed countries. With lack of effective treatment and screening scheme available for the general population, the mortality rate is expected to increase over the next several decades in contrast to the other major malignancies such as lung, breast, prostate and colorectal cancers. Endoscopic ultrasound, with its highest level of detection capacity of smaller pancreatic lesions, is the commonly employed and preferred clinical imaging-based PDAC detection method. Various molecular biomarkers have been investigated for characterization of the disease, but none are shown to be useful or validated for clinical utilization for early detection. As seen from studies of a small subset of familial or genetically high-risk PDAC groups, the higher yield and utility of imaging-based screening methods are demonstrated for these groups. Multiple recent studies on the unique cancer metabolism including PDAC, demonstrate the potential for utility of the metabolites as the discriminant markers for this disease. In order to generate an early PDAC detection screening strategy available for a wider population, we propose to expand the population of higher risk PDAC group with combination clinical and metabolomics parameters.

Role of endoscopic ultrasound in the molecular diagnosis of pancreatic cancer

Pancreatic ductal adenocarcinoma remains one of the most deadly types of tumor. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a safe, cost-effective, and accurate technique for evaluating and staging pancreatic tumors. However, EUS-FNA may be inconclusive or doubtful in up to 20% of cases. This review underlines the clinical interest of the molecular analysis of samples obtained by EUS-FNA in assessing diagnosis or prognosis of pancreatic cancer, especially in locally advanced tumors. On EUS-FNA materials DNA, mRNA and miRNA can be extracted, amplified, quantified and subjected to methylation assay. Kras mutation assay, improves diagnosis of pancreatic cancer. When facing to clinical and radiological presentations of pseudo-tumorous chronic pancreatitis, wild-type Kras is evocative of benignity. Conversely, in front of a pancreatic mass suspected of malignancy, a mutated Kras is highly evocative of pancreatic adenocarcinoma. This strategy can reduce false-negative diagnoses, avoids the delay of making decisions and reduces loss of surgical resectability. Similar approaches are conducted using analysis of miRNA expression as well as Mucin or markers of invasion (S100P, S100A6, PLAT or PLAU). Beyond the diagnosis approach, the prediction of response to treatment can be also investigated form biomarkers expression within EUS-FNA materials.

Next generation sequencing improves the accuracy of KRAS mutation analysis in endoscopic ultrasound fine needle aspiration pancreatic lesions

The use of endoscopic ultrasonography has allowed for improved detection and pathologic analysis of fine needle aspirate material for pancreatic lesion diagnosis. The molecular analysis of KRAS has further improved the clinical sensitivity of preoperative analysis. For this reason, the use of highly analytical sensitive and specific molecular tests in the analysis of material from fine needle aspirate specimens has become of great importance. In the present study, 60 specimens from endoscopic ultrasonography fine needle aspirate were analyzed for KRAS exon 2 and exon 3 mutations, using three different techniques: Sanger sequencing, allele specific locked nucleic acid PCR and Next Generation sequencing (454 GS-Junior, Roche). Moreover, KRAS was also tested in wild-type samples, starting from DNA obtained from cytological smears after pathological evaluation. Sanger sequencing showed a clinical sensitivity for the detection of the KRAS mutation of 42.1%, allele specific locked nucleic acid of 52.8% and Next Generation of 73.7%. In two wild-type cases the re-sequencing starting from selected material allowed to detect a KRAS mutation, increasing the clinical sensitivity of next generation sequencing to 78.95%. The present study demonstrated that the performance of molecular analysis could be improved by using highly analytical sensitive techniques. The Next Generation Sequencing allowed to increase the clinical sensitivity of the test without decreasing the specificity of the analysis. Moreover we observed that it could be useful to repeat the analysis starting from selectable material, such as cytological smears to avoid false negative results.

Multiple KRAS mutations in pancreatic adenocarcinoma: molecular features of neoplastic clones indicate the selection of divergent populations of tumor cells

KRAS is one of the most common genes mutated in pancreatic adenocarcinoma. Multiple KRAS mutations may be detected within the same pancreatic adenocarcinoma, but it is usually unclear whether the different mutations represent biologically irrelevant molecular events or whether they indicate the coexistence of distinct sizable neoplastic clones within a given tumor. We identified a case of pancreatic adenocarcinoma with 5 different mutations in the KRAS gene and have been able to characterize the allelic distribution of the KRAS mutations and the size of the neoplastic clones using allele-specific locked nucleic acid polymerase chain reaction and next-generation sequencing (454 GS-Junior). The results indicate that the tumor is composed of 5 distinct cell populations: one is KRAS G12V mutated (~38% of neoplastic cells), the second is KRAS G12V in one allele and KRAS G12D in the other (~32%), the third is KRAS G12V in one allele and KRAS G12R in the other (~24%), and the fourth is KRAS G12V in one allele and KRAS G12C in the other (~6%). The fifth clone, representing a minority of neoplastic cells, has a KRAS Q61H mutation in addition to one of the above alterations. Microsatellite analysis identified mutation of the NR21 marker out of the 13 tested, indicating that the tumor has a defect in maintaining DNA integrity different from loss of conventional DNA mismatch repair. These results are consistent with the successive selection of divergent populations of tumor cells and underscore the relevance of nucleotide instability in pancreatic adenocarcinoma.

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.

Diagnostic accuracy of K-ras mutation for pancreatic carcinoma: a meta-analysis

BACKGROUND

The conventional tests for the diagnosis of early stage pancreatic carcinoma are not acceptable. This meta-analysis is to evaluate the accuracy of K-ras mutation for the diagnosis of pancreatic carcinoma.

DATA SOURCES

A systemic search of all relevant literature was performed in Web of Science, EMBASE, Cochrane Database, and MEDLINE (PubMed as the search engine) prior to June 1, 2011. Thirty-four studies fulfilled the inclusion criteria and data were pooled for analysis.

RESULTS

The pooled estimates for K-ras mutation in diagnosis of pancreatic carcinoma were as follows: sensitivity 0.68 (95% CI: 0.66-0.71), specificity 0.87 (95% CI: 0.85-0.88), positive likelihood ratio 4.54 (95% CI: 3.47-5.94), negative likelihood ratio 0.37 (95% CI: 0.30-0.44) and diagnostic odds ratio 14.90 (95% CI: 10.02-22.15). Summary receiver operating characteristic analysis demonstrated that the maximum joint sensitivity and specificity was 0.79, and the overall area under the curve was 0.86.

CONCLUSIONS

Diagnostic accuracy of K-ras mutation was not superior to that of conventional tests. Therefore, K-ras mutation analysis alone is not recommended for the diagnosis of pancreatic carcinoma.

Endoscopic ultrasound fine needle aspiration: Technique and applications in clinical practice

Since its initial report in 1992, endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has now been incorporated into the diagnostic and staging algorithm for the evaluation of benign and malignant diseases of the gastrointestinal tract and of adjacent organs. Its introduction constitutes a major breakthrough in the endoscopic field and has gradually transformed EUS from a pure imaging modality into a more interventional. In addition, the possibility of collecting samples, providing a definitive cytological and/or histological evidence of the presence of malignancy, has strongly contributed to changing EUS from a subjective, highly operator dependant procedure into a more objective one. This article will review the instrumentation, technique and the most important clinical applications of EUS-FNA.

Molecular Biologic Approach to the Diagnosis of Pancreatic Carcinoma Using Specimens Obtained by EUS-Guided Fine Needle Aspiration

We review the utility of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), a rapid, safe, cost-effective, and accurate diagnostic modality for evaluating pancreatic tumors. EUS-FNA is currently used for the diagnosis and staging of pancreatic tumors. The sensitivity of EUS-FNA for pancreatic malignancy ranges from 75% to 94%, and its specificity approaches 100% in most studies. However, EUS-FNA has some limitations in the diagnosis of well-differentiated or early-stage cancers. Recent evidence suggests that molecular biological analysis using specimens obtained by EUS-FNA improves diagnostic sensitivity and specificity, especially in borderline cytological cases. It was also reported that additional information regarding patient response to chemotherapy, surgical resectability, time to metastasis, and overall survival was acquired from the genetic analysis of specimens obtained by EUS-FNA. Other studies have revealed that the analysis of KRAS, MUC, p53, p16, S100P, SMAD4, and microRNAs is helpful in making the diagnosis of pancreatic carcinoma. In this paper, we describe the present state of genetic diagnostic techniques for use with EUS-FNA samples in pancreatic diseases. We also discuss the role of molecular biological analyses for the diagnosis of pancreatic carcinoma.

Copy number amplification of the PIK3CA gene is associated with poor prognosis in non-lymph node metastatic head and neck squamous cell carcinoma

Background

Deregulation of the EGFR signaling pathway is one of the most frequently observed genetic abnormalities that drives cancer development. Although mutations in the downstream components of the EGFR signaling pathway, including KRAS, BRAF and PIK3CA, have been reported in numerous cancers, extensive mutation and copy number analysis of these genes in clinical samples has not been performed for head and neck squamous cell carcinoma (HNSCC).

Methods

We examined the mutations and copy number alterations of KRAS, BRAF and PIK3CA in 115 clinical specimens of HNSCC obtained from surgically treated patients.

We used DNA sequencing to detect mutations and the copy number changes were evaluated by qPCR and array comparative genomic hybridization (CGH) analysis.

Results

We examined the mutations and copy number alterations of KRAS, BRAF and PIK3CA in 115 clinical specimens of HNSCC obtained from surgically treated patients. We identified 3 mutations (2.6%) in K-RAS and 3 mutations (2.6%) in PIK3CA. Copy number amplification was found in 37 cases (32.2%) for PIK3CA, 10 cases (8.7%) for K-RAS and 2 cases (1.7%) for BRAF. Kaplan-Meier survival analysis revealed that copy-number amplification of PIK3CA was markedly associated with cancer relapse in patients without lymph node metastasis. (Log-rank test, p = 0.026)

Conclusions

Copy number amplification of the PIK3CA gene is associated with poor prognosis in HNSCC patients without lymph node metastasis. The PIK3CA copy number status will serve as a marker of poor prognosis in patients with HNSCC.

Pancreatico-biliary endoscopic ultrasound: A systematic review of the levels of evidence, performance and outcomes

Our aim was to record pancreaticobiliary endoscopic ultrasound (EUS) literature of the past 3 decades and evaluate its role based on a critical appraisal of published studies according to levels of evidence (LE). Original research articles (randomized controlled trials, prospective and retrospective studies), meta-analyses, reviews and surveys pertinent to gastrointestinal EUS were included. All articles published until September 2011 were retrieved from PubMed and classified according to specific disease entities, anatomical subdivisions and therapeutic applications of EUS. The North of England evidence-based guidelines were used to determine LE. A total of 1089 pertinent articles were reviewed. Published research focused primarily on solid pancreatic neoplasms, followed by disorders of the extrahepatic biliary tree, pancreatic cystic lesions, therapeutic-interventional EUS, chronic and acute pancreatitis. A uniform observation in all six categories of articles was the predominance of LE III studies followed by LE IV, IIb, IIa, Ib and Ia, in descending order. EUS remains the most accurate method for detecting small (< 3 cm) pancreatic tumors, ampullary neoplasms and small (< 4 mm) bile duct stones, and the best test to define vascular invasion in pancreatic and peri-ampullary neoplasms. Detailed EUS imaging, along with biochemical and molecular cyst fluid analysis, improve the differentiation of pancreatic cysts and help predict their malignant potential. Early diagnosis of chronic pancreatitis appears feasible and reliable. Novel imaging techniques (contrast-enhanced EUS, elastography) seem promising for the evaluation of pancreatic cancer and autoimmune pancreatitis. Therapeutic applications currently involve pancreaticobiliary drainage and targeted fine needle injection-guided antitumor therapy. Despite the ongoing development of extra-corporeal imaging modalities, such as computed tomography, magnetic resonance imaging, and positron emission tomography, EUS still holds a leading role in the investigation of the pancreaticobiliary area. The major challenge of EUS evolution is its expanding therapeutic potential towards an effective and minimally invasive management of complex pancreaticobiliary disorders.

Nanofluidic digital PCR for KRAS mutation detection and quantification in gastrointestinal cancer

BACKGROUND

Concomitant quantification of multiple mutant KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) alleles may provide information in addition to that provided by standard mutation-detection procedures. We assessed the feasibility of a nanofluidic digital PCR array platform to detect and quantify KRAS mutations simultaneously in clinically relevant samples.

METHODS

We assessed 2 groups of patients (colorectal and pancreatic disease): Group 1 consisted of 27 patients with colorectal carcinomas, 14 patients with adenomas, and 5 control individuals; group 2 consisted of 42 patients with pancreatic carcinoma, 4 with adenocarcinomas of the ampulla, and 6 with chronic pancreatitis). Digital PCR was performed with the Digital Array Chip (Fluidigm).

RESULTS

Nanofluidic digital PCR detected mutant alleles at 0.05% to 0.1%, depending on the variant analyzed. For the colorectal disease group, conventional PCR detected 9 (64%) of 14 adenomas that were positive for KRAS mutants, whereas digital PCR increased this number to 11 (79%) of 14. Sixteen (59%) of 27 carcinomas showed KRAS mutation with conventional PCR. Two additional cases were detected with digital PCR. In 5 cases (3 adenomas, 2 carcinomas), the total number of mutant alleles changed. For the pancreatic disease group, digital PCR increased the number of positive cases from 26 to 34 (81%) and identified ≥ 2 mutant alleles in 25 cases, compared with conventional PCR, which identified multiple KRAS mutant alleles in only 12 cases. A good correlation was observed between results obtained with tumor biopsies and those obtained with pancreatic juice.

CONCLUSIONS

Digital PCR provides a robust, quantitative measure of the proportion of KRAS mutant alleles in routinely obtained samples. It also allows a better classification of tumors, with potential clinical relevance.

Clinical impact of K-ras mutation analysis in EUS-guided FNA specimens from pancreatic masses

BACKGROUND

EUS-guided FNA (EUS-FNA) is considered optimal for differentially diagnosing pancreatic masses. However, the sensitivity of EUS-FNA ranges from 65% to 95%, respectively, which requires improvement.

OBJECTIVE

To evaluate clinical impact of K-ras mutation analysis in EUS-FNA specimens from pancreatic masses.

DESIGN

Prospective registration, single-center study.

SETTING

Tertiary referral center.

PATIENTS

This study involved 394 consecutive patients with pancreatic masses (307 pancreatic ductal adenocarcinomas [PDACs], 47 pancreatic inflammatory lesions, and 40 other types of tumors) who underwent EUS-FNA and analysis of K-ras mutations.

INTERVENTION

EUS-FNA, Cycleave polymerase chain reaction.

MAIN OUTCOME MEASUREMENTS

Improvement of the diagnostic accuracy by K-ras mutation analysis; absence of K-ras mutations in non-PDAC masses.

RESULTS

K-ras mutations were detected in 266 of 307 PDAC aspirates (87%) and in 3 of 87 non-PDAC masses (3%). K-ras mutations were detected in 18 of 39 patients (46%) who remained cytohistopathologically undiagnosed. The sensitivity, specificity, positive and negative predictive values, and accuracy of cytohistopathological and K-ras mutation analyses alone were 87%, 100%, 100%, 54%, and 89%, respectively, and, when combined, were 93%, 100%, 100%, 68%, and 94%, respectively. Adding K-ras mutation analysis to standard cytohistopathological assessment increased the sensitivity and accuracy of EUS-FNA by 6% (P < .001) and 5% (P < .001), respectively.

LIMITATIONS

Single-center study.

CONCLUSIONS

K-ras mutation analysis may be helpful in patients with suspected PDAC yet inconclusive EUS-FNA findings. K-ras mutations were extremely rare in pancreatic inflammation and other pancreatic tumors.

Levels of evidence in endoscopic ultrasonography: a systematic review

BACKGROUND AND AIMS

A prolific trend currently designates endoscopic ultrasonography (EUS) literature. We aimed to record all EUS-studies published during the past decade and evaluate them in terms of scientific quality, creating a stratification based on levels of evidence (LE).

METHODS

All articles on EUS published between January 2001 and December 2010 were retrieved using a Pubmed and Cochrane Library search. Inclusion criteria were: original research papers (randomized controlled trials-RCTs, prospective and retrospective studies), meta-analyses, reviews and surveys pertinent to gastrointestinal EUS. Levels of evidence (LE) were assessed using the North of England evidence-based guidelines.

RESULTS

Overall, 1,832 eligible articles were reviewed. The majority (46.1%) of reports comprised retrospective descriptive studies (LE III). Expert reviews and committee reports (LE IV) accounted for 28.9%, well-designed quasi-experimental studies (LE IIb) for 20.1%, RCTs (LE Ib) for 2.4%, prospective controlled trials (LE IIa) for 1.4%, and meta-analyses (LE Ia) for 1.1% of the total. High LE (Ia-Ib) were assigned to loco-regional staging of luminal gastrointestinal cancers; mediastinal staging of lung cancer; diagnostic work-up of solid pancreatic tumors, suspected biliary obstruction and choledocholithiasis; celiac plexus neurolysis; and pancreatic pseudocysts drainage. Intermediate to low LE (IIa-IV) were assigned to submucosal tumors, pancreatic cysts, chronic pancreatitis and novel therapeutic applications (pancreato-biliary drainage, tumor ablation).

CONCLUSIONS

Diagnostic and staging EUS has matured and has proven its clinical impact on patient management. Therapeutic or interventional EUS is still evolving and more quality research and data are needed to establish EUS as the best next intervention to perform once firm evidence is available.

Unusual, metastatic, or neuroendocrine tumor of the pancreas: a diagnosis with endoscopic ultrasound-guided fine-needle aspiration and immunohistochemistry

BACKGROUND/AIM

To determine the yield of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in combination with immunostains in diagnosing unusual solid pancreatic masses (USPM) in comparison with pancreatic adenocarcinoma (ACP).

PATIENTS AND METHODS

All EUS-FNA of solid pancreatic masses performed with a 22-gauge needle were included. Data on clinical presentations, mass characteristics, presence of pancreatitis, yield of tissue, and final diagnosis were compared between the two groups. On site cytopathology was provided and additional passes were requested to perform immunostains.

RESULTS

Two hundred and twenty-nine cases with either adenocarcinoma or USPM were included. The median age of the cohort was 65 years. ACP (210/229, 92%) accounted for the majority of the cases. The USPM included neuroendocrine (NET) masses (n=13), metastatic renal carcinoma (n=3), metastatic melanoma (n=1), lymphoma (n=1), and malignant fibrous histiocytoma (n=1). Subjects with ACP were significantly more likely to present with loss of weight (P=0.02) or obstructive jaundice (P<0.001). Subjects with ACP were more likely to have suspicious/atypical FNA biopsy results as compared with USPM (10% vs 0%). The sensitivity of EUS-FNA with immunostains was 93% in ACP as compared with 100% in USPM. Diagnostic accuracy was higher in USPM as compared with ACP (100% vs 93%).

CONCLUSIONS

EUS-FNA using a 22-gauge needle with immunostains has excellent diagnostic yield in patients with USPMs, which is comparable if not superior to the yield in pancreatic adenocarcinoma.