Identification of a novel histone H2A mono-ubiquitination-inhibiting cell-active small molecule.

Histone H2A mono-ubiquitination plays important roles in epigenetic gene expression and is also involved in tumorigenesis. Small molecules controlling H2A ubiquitination are of interest as potential chemical tools and anticancer drugs. To identify novel small molecule inhibitors of H2A ubiquitination, we synthesized and evaluated several compounds designed based on PRT4165 (1), which is a reported histone ubiquitin ligase RING1A inhibitor. We found that compound 11b strongly inhibited the viability and reduced histone H2A mono-ubiquitination in human osteosarcoma U2OS cells. Therefore, compound 11b is a promising lead compound for the development of H2A histone ubiquitination-inhibiting small molecules.

Safety of skipping the tract dilation step for EUS-guided biliary drainage in patients with unresectable malignant biliary obstruction (with video).

BACKGROUND: Thin delivery system stents can be inserted directly without the need for a tract dilation step and are expected to reduce bile leakage during endoscopic ultrasound-guided biliary drainage (EUS-BD). The present study retrospectively compared the safety and efficacy of EUS-BD using a thin metal stent (< 7.5 Fr) with those of EUS-BD using a conventional stent (≥ 7.5 Fr). METHODS: The present study enrolled 112 patients who underwent EUS-BD using metal stents for unresectable malignant biliary obstruction between April 2016 and July 2022. The primary endpoint was the rate of adverse events (AEs). The secondary endpoints were clinical success rate, procedure time, procedure success rate in the absence of the tract dilation step, recurrent biliary obstruction rate, time to biliary obstruction, and overall survival. Risk factors associated with early AEs were also evaluated. RESULTS: The rate of early AEs was significantly lower (12% vs. 35%, P = 0.013) and the procedure success without the tract dilation step was significantly higher (82% vs. 33%, P < 0.001) in the thin than in the conventional delivery system stent group. None of the other secondary endpoints differed significantly between the two groups. Multivariate analysis showed that employing the tract dilation step during EUS-BD was a significant independent risk factor for early AEs (skipping vs. employing; HR, 9.66; 95% CI, 1.13-83.0, P = 0.028). CONCLUSION: Employing the tract dilation step during EUS-BD was a significant risk factor for early AEs. Metal stents with a delivery diameter < 7.5 Fr can be inserted directly without the tract dilation step, resulting in lower early AE rates.

Design, synthesis, and biological evaluation of phenylcyclopropylamine-entinostat conjugates that selectively target cancer cells.

Small molecule-based selective cancer cell-targeting can be a desirable anticancer therapeutic strategy. Aiming to discover such small molecules, we previously developed phenylcyclopropylamine (PCPA)-drug conjugates (PDCs) that selectively release anticancer agents in cancer cells where lysine-specific demethylase 1 (LSD1) is overexpressed. In this work, we designed PCPA-entinostat conjugates for selective cancer cell targeting. PCPA-entinostat conjugate 12 with a 4-oxybenzyl group linker released entinostat in the presence of LSD1 in in vitro assays and selectively inhibited the growth of cancer cells in preference to normal cells, suggesting the potential of PCPA-entinostat conjugates as novel anticancer drug delivery small molecules.

Role of contrast-enhanced harmonic endoscopic ultrasonography (EUS) and EUS elastography in pancreatic lesions.

Pancreatic cancers have a poor prognosis, and their incident rates have risen. Endoscopic ultrasonography (EUS) is an efficient and reliable diagnostic modality for pancreatic lesions, providing high spatial resolution. However, while EUS helps to detect minor pancreatic lesions, nearly all solid pancreatic lesions are hypoechoic, which creates difficulty in making differential diagnoses of pancreatic lesions. When diagnosing pancreatic lesions, the performance of image-enhanced EUS techniques is essential, such as EUS elastography or contrast-enhanced harmonic EUS (CH-EUS). CH-EUS diagnosis is based on assessing the vascularity of lesions, whereas tissue elasticity is measured via EUS elastography. Elastography is either strain or shear-wave, depending on the different mechanical properties being evaluated. The usefulness of enhanced EUS techniques is demonstrated in this review for the differential diagnosis of pancreatic lesions, including solid and cystic lesions, and pancreatic cancer staging.

A Structure-Activity Relationship Study of SNAIL1 Peptides as Inhibitors of Lysine-Specific Demethylase 1.

Peptides have recently garnered attention as middle-molecular-weight drugs with the characteristics of small molecules and macromolecules. Lysine-specific demethylase 1 (LSD1) is a potential therapeutic target for lung cancer, neuroblastoma, and leukemia, and some peptide-based LSD1 inhibitors designed based on the N-terminus of SNAIL1, a member of the SNAIL/SCRATCH family of transcription factors, have been reported. The N-terminus of SNAIL1 peptide acts as a cap of the catalytic site of LSD1, inhibiting interactions with LSD1. However, the structure-activity relationship (SAR) of these inhibitors is not yet fully understood. Therefore, in the present study, we aimed to uncover the SAR and to identify novel SNAIL1 peptide-based LSD1 inhibitors. We synthesized peptide inhibitor candidates based on truncating the N-terminus of SNAIL1 or substituting its amino acid residues. In the truncation study, we found that SNAIL1 1-16 (2), which was composed of 16 residues, strongly inhibited LSD1. Furthermore, we investigated the SAR at residues-3 and -5 from the N-terminus and found that peptides 2j and 2k, in which leucine 5 of the parent peptide is substituted with unnatural amino acids, cyclohexylalanine and norleucine, respectively, strongly inhibited LSD1. This result suggests that the hydrophobic interaction between the inhibitor peptides and LSD1 affects the LSD1-inhibitory activity. We believe that this SAR information provides a basis for the development of more potent LSD1 inhibitors.

Identification of a Histone Deacetylase 8 Inhibitor through Drug Screenings Based on Machine Learning.

Histone deacetylase 8 (HDAC8) is a zinc-dependent HDAC that catalyzes the deacetylation of nonhistone proteins. It is involved in cancer development and HDAC8 inhibitors are promising candidates as anticancer agents. However, most reported HDAC8 inhibitors contain a hydroxamic acid moiety, which often causes mutagenicity. Therefore, we used machine learning for drug screening and attempted to identify non-hydroxamic acids as HDAC8 inhibitors. In this study, we established a prediction model based on the random forest (RF) algorithm for screening HDAC8 inhibitors because it exhibited the best predictive accuracy in the training dataset, including data generated by the synthetic minority over-sampling technique (SMOTE). Using the trained RF-SMOTE model, we screened the Osaka University library for compounds and selected 50 virtual hits. However, the 50 hits in the first screening did not show HDAC8-inhibitory activity. In the second screening, using the RF-SMOTE model, which was established by retraining the dataset including 50 inactive compounds, we identified non-hydroxamic acid 12 as an HDAC8 inhibitor with an IC50 of 842 nM. Interestingly, its IC50 values for HDAC1 and HDAC3-inhibitory activity were 38 and 12 µM, respectively, showing that compound 12 has high HDAC8 selectivity. Using machine learning, we expanded the chemical space for HDAC8 inhibitors and identified non-hydroxamic acid 12 as a novel HDAC8 selective inhibitor.

Protocol for a Multi-Center Confirmatory Trial to Evaluate the Differential Diagnostic Performance of Contrast-Enhanced Ultrasonography Using Perflubutane in Patients with a Pancreatic Mass: A Multicenter Prospective Study.

For pancreatic masses, an evaluation of their vascularity using contrast-enhanced ultrasonography can help improve their characterization. This study was designed to evaluate the utility and safety of contrast-enhanced transabdominal ultrasonography (CE-TUS) and endoscopic ultrasonography (CE-EUS) in the diagnosis of pancreatic masses including solid or cystic masses. This multi-center comparative open-label superiority study is designed to compare Plain (P)-TUS/EUS alone with P-TUS/P-EUS plus CE-TUS/CE-EUS. Three hundred and one patients with a total of 232 solid pancreatic masses and 69 cystic masses were prospectively enrolled. The primary endpoints are to compare the diagnostic accuracy between P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for both the TUS and EUS of solid pancreatic masses, and to compare the diagnostic accuracy between P-EUS alone and P-EUS plus CE-EUS in cystic pancreatic masses. The secondary endpoints are to compare the diagnostic sensitivity and specificity of P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for pancreatic solid/cystic masses, and the accuracy of P-TUS alone and P-TUS plus CE-TUS for pancreatic cystic masses. Other secondary endpoints included comparing the diagnostic sensitivity, specificity, and accuracy of CE-TUS, CE-EUS and CE-computed tomography (CT) for solid/cystic pancreatic masses. The safety, degree of effective enhancement, and diagnostic confidence obtained with CE-TUS/CE-EUS will also be assessed.

Structural optimization of a lysine demethylase 5 inhibitor for improvement of its cellular activity.

Lysine demethylase 5 (KDM5) subfamily proteins are important in epigenetic gene regulation. They are involved in the growth and drug resistance of cancer cells. Therefore, KDM5s are potential cancer therapeutic targets, and their inhibitors hold promise as anti-cancer drugs. Several KDM5 inhibitors, including KDM5-C49 (2a), have exhibited potent KDM5-inhibitory activities in in vitro enzyme assays. However, they do not show enough cellular activity despite being converted to their prodrugs. We hypothesized that their poor lipophilicity should prevent them from sufficiently penetrating the cell membrane, and introducing more lipophilic groups should improve cellular activities. In this study, we investigated 2a and KDM5-C70 (3a), a prodrug of 2a, and attempted to improve its cellular activity by replacing the N,N-dimethyl amino group of 3a with more lipophilic groups. N-Butyl, N-methyl amino compound 2e exhibited potent and selective KDM5-inhibitory activity equal to that of 2a. Furthermore, the cell membrane permeability of 3e, an ethyl ester prodrug of 2e, was six times higher than that of 3a in a parallel artificial membrane permeation assay. In addition, western blot analysis indicated that treating human lung cancer A549 cells with 3e increased histone methylation levels more strongly than that with 3a. Thus, we identified compound 3e as a more cell-active KDM5 inhibitor that has sufficient cell membrane permeability.

Impact of sarcopenia on recurrent biliary obstruction after EUS-guided biliary drainage in patients with malignant biliary obstruction.

BACKGROUND AND AIMS: Sarcopenia is an important prognostic factor for cancer patients. The aim of this study was to assess the ability of sarcopenia to predict recurrent biliary obstruction (RBO) in patients with unresectable cancer after EUS-guided biliary drainage (EUS-BD). METHODS: The study enrolled 113 patients who underwent EUS-BD using the self-expandable metal stent (SEMS) for unresectable malignant biliary obstruction (MBO) between April 2016 and December 2021 at Wakayama Medical University Hospital. The skeletal muscle index at the third lumbar spine level (L3) was calculated from computed tomography images. We analyzed the cumulative incidence of RBO at 180 days after stent insertion. Univariate and multivariate analyses were performed to identify variables significantly associated with RBO. RESULTS: Seventy-six patients were assigned to the sarcopenia group, and 37 were assigned to the non-sarcopenia group. The 180-day cumulative incidence of RBO was 11% in the non-sarcopenia group and 29% in the sarcopenia group (p = 0.034). The time to RBO was significantly shorter for the sarcopenia group (p = 0.028; Gray's test). Multivariate analyses identified sarcopenia as an independent prognostic factor for RBO (present vs absent; HR 4.61; 95% CI 1.76-12.10, p = 0.001). The rates of biliary sludge/food impaction were significantly higher in the sarcopenia group for the causes of RBO (p = 0.048). There were no significant differences between the sarcopenia and the non-sarcopenia groups with respect to related EUS-BD adverse events. CONCLUSION: Sarcopenia is an independent indicator of RBO in patients with MBO who receive EUS-BD with SEMS.

Intraductal Papillary Neoplasm of the Bile Duct Treated with Argon Plasma Coagulation via Endoscopic Ultrasound-guided Choledochoduodenostomy.

A 93-year-old man presented to our hospital with a fever, abdominal pain, and jaundice. Computed tomography revealed bilateral bile duct dilation, cystic lesions with bile duct communication, and intraluminal solid nodules arising from the bile duct wall. The patient was diagnosed with intraductal papillary neoplasm of the bile duct. Surgery was not performed, considering the patient's age. It was impossible to control cholangitis using conventional endoscopic therapy. We therefore created an access route to the bile duct using endoscopic ultrasound-guided choledochoduodenostomy and inserted a lumen-apposed metal stent. Thereafter, we performed argon plasma coagulation of the tumor in the bile duct, which successfully prevented cholangitis recurrence.

Utility of contrast-enhanced harmonic endoscopic ultrasonography for prediction of pathological response after neoadjuvant chemotherapy in patients with pancreatic cancer.

OBJECTIVES: Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) plays an important role in the diagnosis of pancreatic lesions. The aim of this study was to evaluate whether CH-EUS is useful for predicting the treatment efficacy of neoadjuvant chemotherapy (NAC) determined by pathological response. METHODS: Patients who underwent CH-EUS before chemotherapy and surgical resection were divided into two groups according to poor (group-P) or rich tumor vascularity (group-R) determined by enhancement pattern on early- and late-phase CH-EUS. The pathological response to chemotherapy was categorized according to Evans' classification. Pathological analysis showing tumor cell destruction (>50 %) defined a good response. RESULTS: Early-phase CH-EUS classified 44 patients into group-R and 50 into group-P, whereas late-phase CH-EUS classified 10 into group-R and 84 into group-P. Early-phase CH-EUS classification resulted in significantly higher numbers of patients with a good response in the rich group (n = 19) than in the poor group (n = 4; P = 0.0015). Multivariate analysis showed that assignment to the rich group was the strongest independent factor associated with chemosensitivity (P = 0.006, hazard ratio = 5.66, 95 % confidence interval: 1.17-19.27). In resectable patients, the enhancement pattern was the only independent factor associated with chemosensitivity (group-P vs. group-R, P = 0.003; HR [95 % CI], 14.59 [1.38-154.38]). Late-phase CH-EUS did not reveal a significant difference between group-P and group-R. CONCLUSIONS: Evaluation of vascular pattern on CH-EUS could be useful for predicting the efficacy of NAC in patients with pancreatic cancer. The enhancement pattern on CH-EUS could be a one of the useful features for determining NAC indications in resectable pancreatic cancer patients.

Discovery of Selective Histone Deacetylase 1 and 2 Inhibitors: Screening of a Focused Library Constructed by Click Chemistry, Kinetic Binding Analysis, and Biological Evaluation.

Histone deacetylase 1 and 2 (HDAC1/2) inhibitors are potentially useful as tools for probing the biological functions of the isoforms and as therapeutic agents for cancer and neurodegenerative disorders. To discover potent and selective inhibitors, we screened a focused library synthesized by using click chemistry and obtained KPZ560 as an HDAC1/2-selective inhibitor. Kinetic binding analysis revealed that KPZ560 inhibits HDAC2 through a two-step slow-binding mechanism. In cellular assays, KPZ560 induced a dose- and time-dependent increase of histone acetylation and showed potent breast cancer cell growth-inhibitory activity. In addition, gene expression analyses suggested that the two-step slow-binding inhibition by KPZ560 regulated the expression of genes associated with cell proliferation and DNA damage. KPZ560 also induced neurite outgrowth of Neuro-2a cells and an increase in the spine density of granule neuron dendrites of mice. The unique two-step slow-binding character of o-aminoanilides such as KPZ560 makes them interesting candidates as therapeutic agents.

Duodenal bleeding outside covered stents identified by selective computed tomography during arteriography that was successfully treated by embolization: A case report.

The patient was a man in his 60s who previously underwent placement of covered stents in the duodenum for a duodenal stricture caused by pancreatic cancer invasion. He experienced multiple episodes of hematemesis and hematochezia during hospitalization. Emergency upper and lower gastrointestinal endoscopies were performed but were unable to reveal the bleeding source. Based on these findings, we suspected small intestinal bleeding and emergency angiography was performed for the purpose of hemostasis. Computed tomography during arteriography was performed from the superior mesenteric artery and revealed extravasation outside the covered stents in the descending portion of the duodenum. Angiography of the inferior pancreaticoduodenal artery revealed extravasation in the descending portion of the duodenum, and the inferior pancreaticoduodenal artery was embolized with n-butyl cyanoacrylate. There were no postoperative symptoms indicative of intestinal ischemia or pancreatitis, and there was no rebleeding after embolization. In patients with bleeding outside the duodenal-covered stents, it can be difficult to identify the bleeding source by upper gastrointestinal endoscopy. In this case, selective computed tomography during arteriography and angiography revealed bleeding outside the duodenal-covered stents that was successfully treated by arterial embolization with n-butyl cyanoacrylate.

Novel Technique of Endoscopic Ultrasonography for the Differential Diagnosis of Gallbladder Lesions and Intraductal Papillary Mucinous Neoplasms: A Single-Center Prospective Study.

Detective flow imaging endoscopic ultrasonography (DFI-EUS) is an innovative imaging modality that was developed to detect fine vessels and low-velocity blood flow without contrast agents. We evaluate its utility for the differential diagnosis of gallbladder lesions and intraductal papillary mucinous neoplasms (IPMNs). We enrolled patients who underwent DFI-EUS, e-FLOW EUS, and contrast-enhanced EUS for gallbladder lesions or IPMNs. The detection of vessels using DFI-EUS and e-FLOW EUS was compared with that via contrast-enhanced EUS and pathological findings. The vessel pattern was also categorized as regular or irregular. Of the 33 lesions included, there were final diagnoses of 13 IPMNs and 20 gallbladder lesions. DFI-EUS was significantly superior to e-FLOW EUS for discriminating between mural nodules and mucous clots and between solid gallbladder lesions and sludge using the presence or absence of vessel detection in lesions (p = 0.005). An irregular vessel pattern with DFI-EUS was a significant predictor of malignant gallbladder lesions (p = 0.002). DFI-EUS is more sensitive than e-FLOW-EUS for vessel detection and the differential diagnosis of gallbladder lesions and IPMNs. Vessel evaluation using DFI-EUS may be a useful and simple method for differentiating between mural nodules and mucous clots in IPMN, between solid gallbladder lesions and sludge, and between malignant and benign gallbladder lesions.

Comments on and Illustrations of the EFSUMB CEUS Guidelines: Transabdominal and Endoscopic Ultrasound Features of Intrapancreatic Metastases and the Role of Multiparametric Imaging and EUS-Guided Sampling in Rare Pancreatic Tumors.

A definite pathologic diagnosis of intrapancreatic metastasis is crucial for the management decision, i.e., curative or palliative surgery versus chemotherapy or conservative/palliative therapy. This review focuses on the appearance of intrapancreatic metastases on native and contrast-enhanced transabdominal ultrasound and endoscopic ultrasound. Differences and similarities in relation to the primary tumor, and the differential diagnosis from pancreatic carcinoma and neuroendocrine neoplasms are described. The frequency of intrapancreatic metastases in autopsy studies and surgical resection studies will be discussed. Further emphasis is placed on endoscopic ultrasound-guided sampling to confirm the diagnosis.

Uncovered versus covered expandable metal stents for malignant gastric outlet obstruction caused by intrinsic and extrinsic tumors: meta-analysis and meta-regression analysis.

BACKGROUND AND AIMS: Malignant gastric outlet obstruction (GOO) can be palliated by endoscopic placement of self-expandable metal stents (SEMSs). Studies comparing uncovered (USEMSs) and covered (CSEMSs) SEMSs have yielded inconclusive results. This meta-analysis compared USEMSs with CSEMSs in patients with GOO caused by intrinsic and extrinsic tumors. METHODS: Potentially relevant articles were identified by searching PubMed, the Cochrane Library, and Medline. The primary outcome was stent dysfunction. Relationships between characteristics of tumors causing GOO and the stent dysfunction rate following USEMSs and CSEMS placement were assessed. RESULTS: Overall, six randomized controlled trials and 12 observational studies, including 2431 patients, were identified. Rate of stent dysfunction did not differ significantly between USEMSs and CSEMSs (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.73-1.25, I2 = 44%), but there was heterogeneity. Meta-regression analysis showed that heterogeneity of stent dysfunction was caused by a difference in the ratio of intrinsic-to-extrinsic tumors causing GOO between studies (coefficient, 0.944; 95% CI, 0.30-1.58). Studies were divided into intrinsic and extrinsic tumor groups. Subgroup analysis showed that the stent dysfunction rate did not differ between USEMSs and CSEMSs in the intrinsic tumor group (OR, 1.10; 95% CI, 0.85-1.41; I2 = 32%). In the extrinsic tumor group, USEMS was associated with a lower rate of stent dysfunction than CSEMS (OR, 0.64; 95% CI, 0.47-0.87; I2 = 25%). CONCLUSION: USEMS and CSEMS placement generally showed comparable outcomes among patients with GOO. USEMS was more effective than CSEMS for patients with GOO caused by extrinsic tumors.

Shear-wave versus strain elastography in endoscopic ultrasound for the diagnosis of chronic pancreatitis.

BACKGROUND: /Objectives: Endoscopic ultrasound (EUS) elastography is a non-invasive diagnostic method for evaluating tissue elasticity. The aims of this study were to compare shear-wave elastography (SWE) and conventional strain elastography (SE) in determination of the diagnosis and degree of chronic pancreatitis (CP). METHODS: Forty-nine patients who underwent computed tomography (CT), EUS-SWE, EUS-SE, and pancreatic exocrine function testing between January 2019 and January 2022 were prospectively evaluated. CP was diagnosed according to Japan Pancreatic Society criteria (JPSC) 2019, Rosemont criteria (RC), CT findings, and pancreatic exocrine dysfunction. The cut-off values, sensitivity, and specificity for CP diagnosed according to the four criteria were calculated for EUS-SWE and EUS-SE. Relationships between values measured by either of the EUS elastography methods and the number of EUS features were also assessed. RESULTS: EUS-SWE values were positively correlated with the severity grades of RC and JPSC, but EUS-SE values were not. EUS-SWE was significantly better than EUS-SE for diagnosing CP defined according to CT findings (area under the receiver operating characteristics curve [AUROC]: 0.77 vs. 0.61, P < 0.001), RC (AUROC: 0.85 vs. 0.56, P < 0.001), JPSC 2019 (AUROC: 0.83 vs. 0.53, P < 0.001), and exocrine dysfunction (AUROC: 0.78 vs. 0.61, P < 0.001). EUS-SWE values were positively correlated with the number of EUS features, but EUS-SE values were not. CONCLUSIONS: EUS-SWE provides objective assessment for diagnosing and assessing the degree of CP defined according to the criteria of CT findings, RC, JPSC, or exocrine dysfunction, and it can be considered a non-invasive diagnostic tool for CP and exocrine dysfunction.

Contrast-Enhanced Harmonic Endoscopic Ultrasound for Diagnosis of the Aggressiveness of Pancreatic Neuroendocrine Neoplasm.

The purpose of this study is to clarify the associations between the enhancement patterns on contrast-enhanced harmonic endoscopic ultrasound (CH-EUS) and the aggressiveness and prognosis of pancreatic neuroendocrine neoplasms (PanNENs). Patients who underwent CH-EUS and were pathologically diagnosed with PanNEN were included in this study. Patients were divided into three groups according to contrast-enhancement patterns on early-phase and late-phase imaging: "Group A", vascular rich in both phases; "Group B", vascular rich and vascular poor in early and late phases, respectively; "Group C", vascular poor in both phases. Of 39 patients, 25 were assigned to Group A, 7 to Group B, and 7 to Group C. The median overall survival was not reached in Groups A and B and was 335 days in Group C (p < 0.001). The 1-year survival rates were 100% in Group A, 60% in Group B, and 43% in Group C. Patients in Group C showed the shortest overall survival among the three groups. The vascular-poor pattern on late-phase CH-EUS had the highest sensitivity, specificity, and accuracy for aggressive PanNENs among the patterns analyzed on CH-EUS and CECT (84.6%, 91.7%, and 89.2%, respectively). CH-EUS is useful for the diagnosis of and predicting the prognosis of PanNENs.

Comparison of 22G Fork-Tip and Franseen Needles and Usefulness of Contrast-Enhanced Endoscopic Ultrasound for Diagnosis of Upper Gastrointestinal Subepithelial Lesions.

Endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) is less accurate in obtaining samples from gastrointestinal subepithelial lesions (SELs) ≤2 cm than from pancreatic cancers. The present study compared the usefulness of 22G Fork-tip and Franseen needles for EUS-TA and assessed the ability of contrast-enhanced harmonic EUS (CH-EUS) to diagnose SELs ≤2 cm. Fifty-seven patients who underwent EUS-TA for SELs ≤2 cm were evaluated. The primary endpoint was to compare the rate of acquisition of sufficient samples by these two needles. Secondary endpoints included technical success rate, adverse events, numbers of needle passes, and diagnostic ability of CH-EUS for SELs. Of the 57 included patients, 23 and 34 underwent EUS-TA with Fork-tip and Franseen needles, respectively. Technical success rates were 100% with both needles and adverse events occurred in zero (0%) and one (2.9%) patient with Fork-tip and Franseen needles, respectively. The rate of adequate sample acquisition was significantly higher using Fork-tip than Franseen needles (96% vs. 74%; p = 0.038). The hyper- or iso-vascular pattern on CH-EUS correlated significantly with a diagnosis of gastrointestinal stromal tumor (p < 0.001). EUS-TA with Fork-tip needles were superior to EUS-TA with Franseen needles in acquiring sufficient samples and CH-EUS was also useful for the diagnosis of SELs ≤2 cm.