Pathological and Molecular Aspects to Improve Endoscopic Ultrasonography-Guided Fine-Needle Aspiration From Solid Pancreatic Lesions

Tissue processing of endoscopic ultrasound-guided fine-needle aspiration specimens from solid pancreatic lesions

Now that tissue cores can be obtained using fine-needle biopsy (FNB) needles, the ways tissues are handled for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are changing. Direct smear, touch smear of core tissues, and centrifugation have been used for cytological examinations, and liquid-based cytology (LBC), which allows immunostaining and genetic tests that use residual samples, is emerging as an alternative. We emphasize that liquid cytology (Cytospin™ cytology and LBC) is still important, because it enables the diagnosis of pancreatic ductal adenocarcinoma (PDAC) when cancerous cells are scarce in specimens. Cell blocks are being replaced by core tissues obtained via FNB needles. Recent reports indicate that rapid on-site evaluation (ROSE) is not necessary when FNB needles are used, and macroscopic on-site evaluation is used to evaluate specimen adequacy. Macroscopic findings of specimens are helpful in the diagnostic workup and for clarifying specimen-handling methods. In addition to the red strings and white cores observed in PDAC, mixed red and white strings, gray tissues, and gelatinous tissues are observed. Gray (necrotic) tissues and gelatinous (mucus) tissues are more suitable than histology for cell block or cytological processing. Tumor cells in neuroendocrine tumors (NETs) are numerous in red strings but cannot be observed macroscopically. ROSE might thus be necessary for lesions that may be NETs. Core tissues can be used for genetic tests, such as those used for KRAS mutations and comprehensive genomic profiling. Cytological materials, including slides and LBC specimens, can also be genetic test materials.

SI-ViT: Shuffle instance-based Vision Transformer for pancreatic cancer ROSE image classification

BACKGROUND AND OBJECTIVE

The rapid on-site evaluation (ROSE) technique improves pancreatic cancer diagnosis by enabling immediate analysis of fast-stained cytopathological images. Automating ROSE classification could not only reduce the burden on pathologists but also broaden the application of this increasingly popular technique. However, this approach faces substantial challenges due to complex perturbations in color distribution, brightness, and contrast, which are influenced by various staining environments and devices. Additionally, the pronounced variability in cancerous patterns across samples further complicates classification, underscoring the difficulty in precisely identifying local cells and establishing their global relationships.

METHODS

To address these challenges, we propose an instance-aware approach that enhances the Vision Transformer with a novel shuffle instance strategy (SI-ViT). Our approach presents a shuffle step to generate bags of shuffled instances and corresponding bag-level soft-labels, allowing the model to understand relationships and distributions beyond the limited original distributions. Simultaneously, combined with an un-shuffle step, the traditional ViT can model the relationships corresponding to the sample labels. This dual-step approach helps the model to focus on inner-sample and cross-sample instance relationships, making it potent in extracting diverse image patterns and reducing complicated perturbations.

RESULTS

Compared to state-of-the-art methods, significant improvements in ROSE classification have been achieved. Aiming for interpretability, equipped with instance shuffling, SI-ViT yields precise attention regions that identifying cancer and normal cells in various scenarios. Additionally, the approach shows excellent potential in pathological image analysis through generalization validation on other datasets.

CONCLUSIONS

By proposing instance relationship modeling through shuffling, we introduce a new insight in pathological image analysis. The significant improvements in ROSE classification leads to protential AI-on-site applications in pancreatic cancer diagnosis. The code and results are publicly available at https://github.com/sagizty/MIL-SI.

Comparison between three types of needles for endoscopic ultrasound-guided tissue acquisition of pancreatic solid masses: a multicenter observational study

It is debatable which needle has clear superiority of diagnostic performance in endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) of solid pancreatic masses. This study aimed to compare the performance of three needles and determine the variables that affect diagnostic accuracy. From March 2014 to May 2020, 746 patients with solid pancreatic masses who underwent EUS-FNB using three types of needles (Franseen needle, Menghini-tip needle, and Reverse-bevel needle) were retrospectively reviewed. Multivariate analysis using a logistic regression model was used to identify factors related to diagnostic accuracy. There were significant differences between the groups regarding the procurement rate of the histologic and optimal quality cores (Franseen vs. Menghini-tip vs. Reverse-bevel: 98.0% [192/196] vs. 85.8% [97/113] vs. 91.9% [331/360], P < 0.001 and 95.4% [187/196] vs. 65.5% [74/113] vs. 88.3% [318/360], P < 0.001, respectively). The sensitivity and accuracy using histologic samples were 95.03% and 95.92% for Franseen, 82.67% and 88.50% for Menghini-tip, and 82.61% and 85.56% for Reverse-bevel needles, respectively. In direct comparison between the needles using histologic samples, the Franseen needle showed significantly superior accuracy than the Menghini-tip (P = 0.018) and Reverse-bevel needles (P < 0.001). Multivariate analysis indicated that tumor size ≥ 2 cm (odds ratio [OR] 5.36, 95% confidence interval [CI] 3.40-8.47, P < 0.001) and fanning technique (OR 1.70, 95% CI 1.00-2.86, P = 0.047) were significantly associated with an accurate diagnosis. EUS-FNB using the Franseen needle enables the acquisition of a larger and more adequate histologic core tissue and achieves an accurate histological diagnosis when using the fanning technique.

Simultaneous multiple primary malignancies diagnosed by endoscopic ultrasound-guided fine-needle aspiration: A case report

BACKGROUND

Multiple primary malignancies (MPMs) refer to more than one primary malignancy in the same or separate organs of the same patient, and MPMs are considered when different histological characteristics are detected in epidemiological studies. Herein, we report a case presumed to be primary pancreatic cancer with multiple liver metastases by positron-emission tomography/computed tomography (PET/CT) and confirmed to be synchronous liver and pancreatic MPMs by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA).

CASE SUMMARY

A 50-year-old man was referred to our hospital due to abdominal discomfort for 2 mo. Abdominal CT at a local hospital revealed a pancreatic mass with multiple liver nodules. After being transferred to our hospital, PET/CT confirmed all these lesions to have elevated metabolic activity, and therefore primary pancreatic cancer with multiple liver metastases was considered. EUS-guided liver aspiration unexpectedly found signet-ring cells with a high Ki-67 positive rate (20%), while EUS-guided pancreatic aspiration detected pancreatic neuroendocrine cells with a relatively low Ki-67 positive rate (1%). The final diagnosis from the multidisciplinary team was simultaneous liver and pancreatic MPMs. The patient returned to his local hospital for neoadjuvant chemotherapy and surgery, and he is still alive during the 6-mo postoperative follow-up.

CONCLUSION

Although rare, MPMs should be considered when treating pancreatic mass with suspected metastatic lesions, and EUS-FNA has proved minimally invasive and accurate.

Efficacy of endoscopic samplings during initial biliary drainage for cases of pancreatic head cancer: United diagnostic yields of multiple pathological samplings

BACKGROUND/OBJECTIVES

The diagnostic ability of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been fully studied; however, the efficacy of other endoscopic samplings (OESs) is less clear. The aim of this study was to examine the diagnostic efficacies of OESs for pancreatic head cancer (PHC).

METHODS

The diagnostic efficacies of endoscopic samplings were retrospectively analyzed in 448 PHC cases and 63 cases of mass-forming pancreatitis (MFP) during initial transpapillary biliary drainage. The OESs included duodenal biopsy (118 PHCs and 50 MFPs), biliary biopsy (218 and 51) with cytology (368 and 53), and pancreatic duct biopsy (23 and 13) with cytology (56 and 43). EUS-FNA was conducted in a different session (149 and 62). Factors associated with OES sensitivity were analyzed. The sensitivity of biliary biopsy was compared between 1.95 mm and 1.8 mm forceps.

RESULTS

Cancer cells were confirmed in 87.9% of the EUS-FNA samplings and in 64.1% (268/418) obtained by combined OESs (average 1.7 OES types per case): 68.6% by duodenal biopsy, 59.6% by biliary biopsy, 32.6% by biliary cytology, 73.9% by pancreatic duct biopsy, and 33.9% by pancreatic duct cytology. No MFP cases revealed cancer by any sampling. OESs did not increase adverse events. Duodenal stenosis, serum bilirubin, tumor size, and pancreatic juice amounts were associated with OES sensitivity. Biliary biopsy had the same sensitivity with different forceps.

CONCLUSION

EUS-FNA was the most diagnostic protocol; however, OESs can be safely applied during the initial biliary drainage to reduce the demand for EUS-FNA while providing good diagnostic yields.

[Clinical and Technical Guideline for Endoscopic Ultrasound-guided Tissue Acquisition of Pancreatic Solid Tumor: Korean Society of Gastrointestinal Endoscopy]

Endoscopic ultrasound (EUS)-guided tissue acquisition of pancreatic solid tumor requires a strict recommendation for its proper use in clinical practice because of its technical difficulty and invasiveness. The Korean Society of Gastrointestinal Endoscopy appointed a Task Force to draft clinical practice guidelines for EUS-guided tissue acquisition of pancreatic solid tumor. The strength of recommendation and the level of evidence for each statement were graded according to the Minds Handbook for Clinical Practice Guideline Development 2014. The committee, comprising a development panel of 16 endosonographers and an expert on guideline development methodology, developed 12 evidence-based recommendations in eight categories intended to help physicians make evidence- based clinical judgments with regard to the diagnosis of pancreatic solid tumor. This clinical practice guideline discusses EUS-guided sampling in pancreatic solid tumor and makes recommendations on circumstances that warrant its use, technical issues related to maximizing the diagnostic yield (e.g., needle type, needle diameter, adequate number of needle passes, sample obtaining techniques, and methods of specimen processing), adverse events of EUS-guided tissue acquisition, and learning-related issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This guideline may not be applicable for all clinical situations and should be interpreted in light of specific situations and the availability of resources. It will be revised as necessary to cover progress and changes in technology and evidence from clinical practice.

Clinical and Technical Guideline for Endoscopic Ultrasound (EUS)-Guided Tissue Acquisition of Pancreatic Solid Tumor: Korean Society of Gastrointestinal Endoscopy (KSGE)

Endoscopic ultrasound (EUS)-guided tissue acquisition of pancreatic solid tumor requires a strict recommendation for its proper use in clinical practice because of its technical difficulty and invasiveness. The Korean Society of Gastrointestinal Endoscopy (KSGE) appointed a task force to draft clinical practice guidelines for EUS-guided tissue acquisition of pancreatic solid tumor. The strength of recommendation and the level of evidence for each statement were graded according to the Minds Handbook for Clinical Practice Guideline Development 2014. The committee, comprising a development panel of 16 endosonographers and an expert on guideline development methodology, developed 12 evidence-based recommendations in eight categories intended to help physicians make evidence-based clinical judgments with regard to the diagnosis of pancreatic solid tumor. This clinical practice guideline discusses EUS-guided sampling in pancreatic solid tumor and makes recommendations on circumstances that warrant its use, technical issues related to maximizing the diagnostic yield (e.g., needle type, needle diameter, adequate number of needle passes, sample obtaining techniques, and methods of specimen processing), adverse events of EUS-guided tissue acquisition, and learning-related issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This guideline may not be applicable for all clinical situations and should be interpreted in light of specific situations and the availability of resources. It will be revised as necessary to cover progress and changes in technology and evidence from clinical practice. (Gut Liver 2021;15:-374)

Clinical and Technical Guideline for Endoscopic Ultrasound (EUS)-Guided Tissue Acquisition of Pancreatic Solid Tumor: Korean Society of Gastrointestinal Endoscopy (KSGE)

Endoscopic ultrasound (EUS)-guided tissue acquisition of pancreatic solid tumor requires a strict recommendation for its proper use in clinical practice because of its technical difficulty and invasiveness. The Korean Society of Gastrointestinal Endoscopy (KSGE) appointed a Task Force to draft clinical practice guidelines for EUS-guided tissue acquisition of pancreatic solid tumor. The strength of recommendation and the level of evidence for each statement were graded according to the Minds Handbook for Clinical Practice Guideline Development 2014. The committee, comprising a development panel of 16 endosonographers and an expert on guideline development methodology, developed 12 evidence-based recommendations in 8 categories intended to help physicians make evidence-based clinical judgments with regard to the diagnosis of pancreatic solid tumor. This clinical practice guideline discusses EUS-guided sampling in pancreatic solid tumor and makes recommendations on circumstances that warrant its use, technical issues related to maximizing the diagnostic yield (e.g., needle type, needle diameter, adequate number of needle passes, sample obtaining techniques, and methods of specimen processing), adverse events of EUS-guided tissue acquisition, and learning-related issues. This guideline was reviewed by external experts and suggests best practices recommended based on the evidence available at the time of preparation. This guideline may not be applicable for all clinical situations and should be interpreted in light of specific situations and the availability of resources. It will be revised as necessary to cover progress and changes in technology and evidence from clinical practice.

Detecting Early Pancreatic Cancer: Current Problems and Future Prospects

The number of patients with pancreatic cancer (PC) is currently increasing in both Korea and Japan. The 5-year survival rate of patients with PC 13.0%; however, resection with minimal invasion (tumor size: ≤10 mm) increases the 5-year survival rate to 80%. For this reason, early detection is essential, but most patients with early-stage PC are asymptomatic. Early detection of PC has been reported to require screening of high-risk individuals (HRIs), such as those with a family history of PC, inherited cancer syndromes, intraductal papillary mucinous neoplasm, or chronic pancreatitis. Studies on screening of these HRIs have confirmed a significantly better prognosis among patients with PC who were screened than for patients with PC who were not screened. However, to date in Japan, most patients with early-stage PC diagnosed in routine clinics were not diagnosed during annual health checks or by surveillance; rather, PC was detected in these patients by incidental findings during examinations for other diseases. We need to increase the precision of the PC screening and diagnostic processes by introducing new technologies, and we need to pay greater attention to incidental clinical findings.

Safety and efficacy of ultrasound-guided percutaneous coaxial core biopsy of pancreatic lesions: a retrospective study

BACKGROUND AND OBJECTIVE

Pancreatic cancer tumors are difficult to access for biopsy. The use of coaxial needles during ultrasound (US)-guided coarse needle biopsy (CNB) may help to improve specimen collection yields and avoid tissue damage. In this retrospective study, the safety, efficacy, and clinical benefits of US-guided percutaneous coaxial CNB of pancreatic masses were evaluated and compared to those of non-coaxial CNB.

METHODS

A total sample of 220 biopsies performed from August 2015 to August 2019 were analyzed, including 114 performed with a coaxial needle (17-gauge coaxial coarse needle combined with an 18-gauge coarse biopsy needle) and 106 performed with a non-coaxial needle (18-gauge coarse biopsy needle without a coaxial sheath). The coaxial CNB group was stratified by lesion location to further evaluate the applicability of coaxial core needles. The satisfactory specimen rate, diagnostic efficiency, operating time, and complication rate were compared statistically between groups and subgroups.

RESULTS

Compared to the non-coaxial CNB group, the coaxial CNB group had a greater satisfactory specimen rate (98.3% vs. 92.3%; p = 0.048), a lesser mean operating time (8.9 ± 3.27 min vs. 16.8 ± 5.77 min; p < 0.001), and a lower complication rate (2.6% vs. 9.6%, p =0 .04). A better diagnostic efficiency was obtained for coaxial CNBs in the head of pancreas (98.7%) than in the body or tail of the pancreas (90%, p = 0.047).

CONCLUSION

For pancreatic masses, coaxial CNB can yield a higher satisfactory sample rate, lower complication rate, and shorter operating time than non-coaxial biopsy. US-guided percutaneous coaxial CNB is a safe and efficient puncture technique for pancreatic lesion diagnosis.

[Diagnostic quality of transluminal biopsy in undetermined biliary duct stenosis by primary PTCD with "cross and push" technique - a prospective monocentric pilot study]

BACKGROUND

 Histological characterisation of a biliary duct stenosis can be essential for further therapeutic steps. Access to the stenosis is not given in every patient by endoscopic retrograde cholangiography. In these cases, a percutaneous transhepatic cholangiodrainage (PTCD) may be helpful. The optimal preparation and diagnostic precision of taking a biopsy by PTCD is not sufficiently evaluated.

METHODS

 After a training phase of 10 patients, PTCDs in 30 patients with a biliary duct stenosis and lack of adequate drainage by ERC were done in a time range of 24 months. The stenosis was passed with a wire and then a directed forceps-biopsy was performed in a "cross and push" technique (Transluminal Biliary Biopsy Forceps Set, Cook Medical™), using a wire-guided introducer (7 Fr. inner diameter). The result of the histological survey was then correlated with the definite diagnosis. The follow-up time was 18 months.

RESULT

 Out of 30 patients, there were 22 (73 %) with a malignant stenosis (10 biliary duct neoplasms, 12 non-biliary carcinoma/metastases/lymphomas). Eight (27 %) out of 30 patients had a benign stenosis. In case of all 30 patients, there was enough tissue gained by biopsy for histologic survey. Sub-group analysis was performed for biliary duct cancer and non-biliary cancer. Thereby, 8 out of 10 patients with biliary duct neoplasms were also classified as malignant by histology (sensitivity 80 %); whereas, only 8 out of 12 non-biliary cancers could be histologically classified as malignant (sensitivity 66.6 %, difference not significant, p = 0.0577). In all patients with benign stenosis, histological evaluation of biopsies revealed benign histology (specificity 100 %). There were no intervention-related complications.

CONCLUSION

 This prospective cohort-study shows a high diagnostic precision for the percutaneous transductal biopsy-set to evaluate an undetermined biliary duct stenosis-particularly in biliary processes. Because it can be difficult to gain histology in malignant biliary duct processes using different methods, the "cross and push" biopsy completes the spectrum of diagnostic procedures.

Comparison between Conventional Smear and Liquid-Based Preparation in Endoscopic Ultrasonography-Fine Needle Aspiration Cytology of Pancreatic Lesions

The present study aimed to compare the diagnostic accuracy between conventional smear (CS) and liquid-based preparation (LBP) in endoscopic ultrasonography-fine needle aspiration cytology (EUS-FNAC) of pancreatic lesions. Using 31 eligible studies, the diagnostic accuracy of cytologic examination in CS and LBP was evaluated through a conventional meta-analysis and diagnostic test accuracy review. Overall concordance rates were 82.8% (95% confidence interval [CI], 79.8–85.5%) and 94.0% (95% CI, 84.4–97.8%) in CS and LBP, respectively. CS with rapid on-site evaluation (ROSE) showed a higher concordance rate than CS without ROSE. In CS, the pooled sensitivity and specificity were 89.8% (95% CI, 85.2–93.1%) and 95.0% (95% CI, 90.0–97.6%), respectively. The diagnostic odds ratio (OR) and area under curve (AUC) of the summary receiver operating characteristic (SROC) curve were 90.32 (95% CI, 43.85–147.11) and 0.945, respectively. In LBP, the pooled sensitivity and specificity were 80.9% (95% CI, 69.7–88.7%) and 99.9% (95% CI, 1.5–100.0%), respectively. The diagnostic OR and AUC of the SROC curve were 57.21 (95% CI, 23.61–138.64) and 0.939, respectively. Higher concordance rates were found in CS with ROSE and LBP in EUS-FNAC of pancreatic lesions. Regardless of the cytologic preparation method, EUS-FNAC is a useful and accurate diagnostic tool for pancreatic lesions.

Surveillance of Individuals with a Family History of Pancreatic Cancer and Inherited Cancer Syndromes: A Strategy for Detecting Early Pancreatic Cancers

A family history of pancreatic cancer (PC) is a risk factor of PC, and risk levels increase as affected families grow in number and/or develop PC at younger ages. Familial pancreatic cancer (FPC) is defined as a client having at least two PC cases in a first degree relatives. In the narrow sense, FPC does not include some inherited cancer syndromes that are known to increase the risks of PC, such as Peutz-Jeghers syndrome (PJS), hereditary pancreatitis (HP), hereditary breast ovarian cancer syndrome (HBOC), and so on. FPC accounts for 5%-10% of total PC diagnoses and is marked by several features in genetic, epidemiological, and clinicopathological findings that are similar to or distinct from conventional PC. Recent advances in genetic medicine have led to an increased ability to identify germline variants of cancer-associated genes. To date, high-risk individuals (HRIs) in many developed countries, including FPC kindreds and inherited cancer syndromes, are screened clinically to detect and treat early-stage PC. This article highlights the concept of FPC and the most recent data on its detection.

Diagnostic Efficacy of Liquid-Based Cytology in Endoscopic Ultrasound-Guided Fine Needle Aspiration for Pancreatic Mass Lesions During the Learning Curve: A Retrospective Study

OBJECTIVES

The diagnostic yield of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) cytology widely varies depending on the treatment method used. Liquid-based cytology (LBC) has gained popularity in the gynecological field because of its efficacy in collection of target cells and simplicity in the manipulation of specimens. Since the introduction of EUS-FNA at our institution, we have used LBC for the diagnosis of pancreatic mass lesions. This study aims to investigate the diagnostic efficacy of EUS-FNA with LBC in patients with pancreatic mass lesions during the learning curve for EUS-FNA.

METHODS

In this study, we retrospectively enrolled 222 patients with pancreatic mass lesions who were diagnosed using EUS-FNA with LBC between 2011 and 2016. The diagnostic yields for EUS-FNA with LBC for pancreatic mass lesions were evaluated.

RESULTS

The diagnostic sensitivity, specificity, and accuracy for malignancy were found to be 93.9%, 95.1%, and 94.1%, respectively.

CONCLUSIONS

This study suggests that EUS-FNA with LBC for specimens provides good diagnostic efficacy in patients with pancreatic mass lesions even during the learning curve for EUS-FNA.

Benefit of high negative pressure during endoscopic ultrasound-guided fine-needle aspiration with standard 22-gauge needles for pancreatic lesions: a retrospective comparative study

OBJECTIVES

Few studies are available on high negative pressure (HNP) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). This study compared the diagnostic yield between HNP and normal negative pressure (NNP) during EUS-FNA for solid pancreatic masses.

METHODS

Consecutive patients with pancreatic masses who underwent EUS-FNA using a 22-G needle with either HNP or NNP for both the first and second passes were retrospectively examined for diagnostic yield. Rapid on-site evaluation (ROSE) was unavailable at our center. The main outcome measures were the number of passes, diagnostic accuracy and quantity of histological samples.

RESULTS

Two hundred patients underwent EUS-FNA (n = 97, HNP; n = 103, NNP) over a 22-month period. A significantly lower median number of passes was required for HNP than for NNP (2 vs. 3; p < .001). There was no significant difference in diagnostic accuracy between the two groups. The rate of obtaining a histological sample larger than a 10× power field in length was significantly higher for HNP than for NNP (76.4% vs. 59.6%; p = .0019). In the multivariate analysis, a large tumor size (>20 mm) and HNP were identified as factors influencing the acquisition of a larger histological sample.

CONCLUSIONS

There was no significant difference in diagnostic accuracy between HNP and NNP. HNP required fewer passes without ROSE and was related to the acquisition of a larger histological sample. HNP may be useful when few samples are available for EUS-FNA with NNP or a larger histological sample is needed.

Abnormal immunolabelling of SMAD4 in cell block specimens to distinguish malignant and benign pancreatic cells

BACKGROUND

Accurate diagnosis of malignant and benign pancreatic lesions can be challenging, especially with endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) samples that are small and/or degraded. In the present study, we determined how to best evaluate abnormal SMAD4 expression by immunohistochemical staining on cell block specimens from EUS-FNA samples.

RESULTS

In surgically resected pancreas, when abnormal SMAD4 immunolabelling was evaluated as negative SMAD4 expression, the sensitivity was low (33%), but when it was evaluated as decreased SMAD4 expression, the sensitivity improved (53%). Specificity and positive predictive value were high for both evaluations. There were no false-positive cases. In cell block specimens, decreased SMAD4 expression showed 47% sensitivity and 72% specificity, while negative SMAD4 expression showed lower sensitivity (20%) and higher specificity (100%). Both evaluations in cell block specimens showed lower sensitivity and specificity compared to resected specimens. False-positive and -negative rates were higher for cell blocks than for resected specimens.

CONCLUSIONS

Decreased SMAD4 immunolabelling provided improved sensitivity as compared to negative SMAD4 immunolabelling; therefore, it is important to compare SMAD4 expression in a sample to its expression in normal cells. Abnormal SMAD4 labelling showed low sensitivity and high specificity; therefore, SMAD4 staining using EUS-FNA samples might be helpful to detect malignancies that possess SMAD4 gene abnormalities.