Performance of a Shotgun Prediction Model for Colorectal Cancer When Using 16S rRNA Sequencing Data.

Colorectal cancer (CRC), the third most common cancer globally, has shown links to disturbed gut microbiota. While significant efforts have been made to establish a microbial signature indicative of CRC using shotgun metagenomic sequencing, the challenge lies in validating this signature with 16S ribosomal RNA (16S) gene sequencing. The primary obstacle is reconciling the differing outputs of these two methodologies, which often lead to divergent statistical models and conclusions. In this study, we introduce an algorithm designed to bridge this gap by mapping shotgun-derived taxa to their 16S counterparts. This mapping enables us to assess the predictive performance of a shotgun-based microbiome signature using 16S data. Our results demonstrate a reduction in performance when applying the 16S-mapped taxa in the shotgun prediction model, though it retains statistical significance. This suggests that while an exact match between shotgun and 16S data may not yet be feasible, our approach provides a viable method for comparative analysis and validation in the context of CRC-associated microbiome research.

Underwater cap-suction pseudopolyp formation for endoscopic mucosal resection: a simple technique for treating flat, appendiceal orifice or ileocecal valve colorectal lesions.

BACKGROUND: We aimed to evaluate the safety and technical success of an easy-to-use technique that applies underwater cap suction pseudopolyp formation to facilitate the resection of flat lesions or those at the appendiceal orifice or ileocecal valve. METHODS: We retrospectively analyzed a register of consecutive cap suction underwater endoscopic mucosal resection (CAP-UEMR) procedures performed at two centers between September 2020 and December 2021. Procedures were performed using a cone-shaped cap, extending 7 mm from the endoscope tip, to suction the lesion while submerged underwater, followed by underwater snare resection. Our primary end point was technical success, defined as macroscopic complete resection. RESULTS: We treated 83 lesions (median size 20 mm; interquartile range [IQR] 15-30 mm) with CAP-UEMR: 64 depressed or flat lesions (18 previously manipulated, 9 with difficult access), 11 from the appendix, and 8 from the ileocecal valve. Technical success was 100 %. There were seven intraprocedural bleedings and two delayed bleedings, all managed endoscopically. No perforations or other complications occurred. Among the 64 lesions with follow-up colonoscopy, only one recurrence was detected, which was treated endoscopically. CONCLUSIONS: CAP-UEMR was a safe and effective technique for removing nonpolypoid colorectal lesions, including those arising from the appendiceal orifice or ileocecal valve.

Meta-Analysis and Validation of a Colorectal Cancer Risk Prediction Model Using Deep Sequenced Fecal Metagenomes.

The gut microbiome is a potential modifiable risk factor for colorectal cancer (CRC). We re-analyzed all eight previously published stool sequencing data and conducted an MWAS meta-analysis. We used cross-validated LASSO predictive models to identify a microbiome signature for predicting the risk of CRC and precancerous lesions. These models were validated in a new study, Colorectal Cancer Screening (COLSCREEN), including 156 participants that were recruited in a CRC screening context. The MWAS meta-analysis identified 95 bacterial species that were statistically significantly associated with CRC (FDR < 0.05). The LASSO CRC predictive model obtained an area under the receiver operating characteristic curve (aROC) of 0.81 (95%CI: 0.78−0.83) and the validation in the COLSCREEN dataset was 0.75 (95%CI: 0.66−0.84). This model selected a total of 32 species. The aROC of this CRC-trained model to predict precancerous lesions was 0.52 (95%CI: 0.41−0.63). We have identified a signature of 32 bacterial species that have a good predictive accuracy to identify CRC but not precancerous lesions, suggesting that the identified microbes that were enriched or depleted in CRC are merely a consequence of the tumor. Further studies should focus on CRC as well as precancerous lesions with the intent to implement a microbiome signature in CRC screening programs.

Polygenic risk score across distinct colorectal cancer screening outcomes: from premalignant polyps to colorectal cancer.

BACKGROUND: Different risk-based colorectal cancer (CRC) screening strategies, such as the use of polygenic risk scores (PRS), have been evaluated to improve effectiveness of these programs. However, few studies have previously assessed its usefulness in a fecal immunochemical test (FIT)-based screening study. METHODS: A PRS of 133 single nucleotide polymorphisms was assessed for 3619 participants: population controls, screening controls, low-risk lesions (LRL), intermediate-risk (IRL), high-risk (HRL), CRC screening program cases, and clinically diagnosed CRC cases. The PRS was compared between the subset of cases (n = 648; IRL+HRL+CRC) and controls (n = 956; controls+LRL) recruited within a FIT-based screening program. Positive predictive values (PPV), negative predictive values (NPV), and the area under the receiver operating characteristic curve (aROC) were estimated using cross-validation. RESULTS: The overall PRS range was 110-156. PRS values increased along the CRC tumorigenesis pathway (Mann-Kendall P value 0.007). Within the screening subset, the PRS ranged 110-151 and was associated with higher risk-lesions and CRC risk (ORD10vsD1 1.92, 95% CI 1.22-3.03). The cross-validated aROC of the PRS for cases and controls was 0.56 (95% CI 0.53-0.59). Discrimination was equal when restricted to positive FIT (aROC 0.56), but lower among negative FIT (aROC 0.55). The overall PPV among positive FIT was 0.48. PPV were dependent on the number of risk alleles for positive FIT (PPVp10-p90 0.48-0.57). CONCLUSIONS: PRS plays an important role along the CRC tumorigenesis pathway; however, in practice, its utility to stratify the general population or as a second test after a FIT positive result is still doubtful. Currently, PRS is not able to safely stratify the general population since the improvement on PPV values is scarce.

Ways to perform an endoscopic tattoo. Prospective and randomized study in patients with colorectal neoplasm.

BACKGROUND AND AIMS: intraoperative identification of colonic lesions previously detected via colonoscopy may be difficult. Endoscopic tattooing facilitates identification, but there is no evidence regarding which is the best tattoo technique. The goal of the study was to describe the efficacy and safety of endoscopic tattooing and to detect technical and clinical factors associated with its efficacy. PATIENTS AND METHODS: a prospective and randomized study was performed. All tattoo candidate patients were included prior to surgery and randomized into four groups; tattoo at two or three injection points and with a volume of 1 or 1.5 ml of labeling. Multiple variables were registered. RESULTS: one hundred and ninety-five patients were included with an endoscopic tattoo and who subsequently underwent a surgical intervention, the mean age was 70.1 years and 67.2 % were male. The laparoscopic approach was applied in 57.9 % of cases. The intraoperative visibility of the endoscopic tattoo was 89.7 % and 30 % of rectal lesions were not visible. Excluding the rectum, the marking was visible intraoperatively in 92 % of patients, without significant differences according to the surgical approach, the type of marking or any of the variables collected. The tattoo was safe in 92.3 % of the cases. The adverse effect rate was 7.7 % and none of the complications were clinically significant. There were no significant differences between any variables collected in relation to adverse effects. CONCLUSIONS: endoscopic colon tattoo is safe and effective regardless of the technique used. We recommend the technique of two injection points and 1 ml of marking volume for its simplicity, efficiency and safety.

Gut microbiome diversity detected by high-coverage 16S and shotgun sequencing of paired stool and colon sample.

The gut microbiome has a fundamental role in human health and disease. However, studying the complex structure and function of the gut microbiome using next generation sequencing is challenging and prone to reproducibility problems. Here, we obtained cross-sectional colon biopsies and faecal samples from nine participants in our COLSCREEN study and sequenced them in high coverage using Illumina pair-end shotgun (for faecal samples) and IonTorrent 16S (for paired feces and colon biopsies) technologies. The metagenomes consisted of between 47 and 92 million reads per sample and the targeted sequencing covered more than 300 k reads per sample across seven hypervariable regions of the 16S gene. Our data is freely available and coupled with code for the presented metagenomic analysis using up-to-date bioinformatics algorithms. These results will add up to the informed insights into designing comprehensive microbiome analysis and also provide data for further testing for unambiguous gut microbiome analysis.

Seroepidemiology of Toxoplasma gondii in domestic cattle, sheep, goats and pigs from São Tomé and Príncipe.

Despite the global importance of the zoonotic parasite Toxoplasma gondii, little is known regarding its infection in the Democratic Republic of São Tomé and Príncipe (DRSTP). This is the first report of antibodies to T. gondii in cattle, sheep, goats and pigs from the DRSTP. Antibodies were assessed by the modified agglutination test (MAT), with a cut-off titer of 100 for cattle and 20 for sheep, goats and pigs. The present study revealed an overall seroprevalence of 55.8%; 27.1% in 48 cattle, 68.4% in 98 sheep, 70.1% in 97 goats and 43.7% in 103 pigs. The south geographical area for cattle, the central area for sheep, and adult age and living in the central region for goats were found to be risk factors for seropositivity to T. gondii. These results support the scenario of a considerable presence of sporulated oocysts as well as of infected intermediate hosts in the local environment. Consumption of raw or undercooked meat should be considered as an important potential source of infection for animals and humans in the DRSTP.

Seroepidemiology of Toxoplasma gondii in domestic cattle, sheep, goats and pigs from São Tomé and Príncipe / Soroepidemiologia de Toxoplasma gondii em bovinos, ovinos, caprinos e suínos domésticos de São Tomé e Príncipe

Abstract Despite the global importance of the zoonotic parasite Toxoplasma gondii, little is known regarding its infection in the Democratic Republic of São Tomé and Príncipe (DRSTP). This is the first report of antibodies to T. gondii in cattle, sheep, goats and pigs from the DRSTP. Antibodies were assessed by the modified agglutination test (MAT), with a cut-off titer of 100 for cattle and 20 for sheep, goats and pigs. The present study revealed an overall seroprevalence of 55.8%; 27.1% in 48 cattle, 68.4% in 98 sheep, 70.1% in 97 goats and 43.7% in 103 pigs. The south geographical area for cattle, the central area for sheep, and adult age and living in the central region for goats were found to be risk factors for seropositivity to T. gondii. These results support the scenario of a considerable presence of sporulated oocysts as well as of infected intermediate hosts in the local environment. Consumption of raw or undercooked meat should be considered as an important potential source of infection for animals and humans in the DRSTP.

Resumo Apesar da importância global do parasita zoonótico Toxoplasma gondii, pouco se conhece sobre sua infecção na República Democrática de São Tomé e Príncipe (RDSTP). Esse é o primeiro relato de anticorpos para T. gondii em bovinos, ovinos, caprinos e suínos da RDSTP. Os anticorpos foram pesquisados pelo teste de aglutinação direta modificada (TADM), com um título de corte de 100 para bovinos e de 20 para ovinos, caprinos e suínos. O presente estudo revelou uma soroprevalência global de 55,8%: 27,1% em 48 bovinos, 68,4% em 98 ovinos, 70,1% em 97 caprinos e 43,7% em 103 suínos. A área geográfica sul para os bovinos, a área central para os ovinos, bem como a idade adulta e a região central para os caprinos foram considerados fatores de risco para soropositividade a T. gondii. Esses resultados suportam o cenário de uma considerável presença de oocistos esporulados, bem como de hospedeiros intermediários infectados no ambiente local. O consumo de carne crua ou mal passada deve ser considerado como uma importante fonte potencial de infecção para animais e seres humanos na RDSTP.

Single-stage approach for the management of choledocolithiasis with concomitant cholelithiasis. Implementation of a protocol in a secondary hospital.

BACKGROUND: Current evidence shows that single-stage treatment of concomitant choledocholithiasis and cholelithiasis is as effective and safe as two-stage treatment. However, several studies suggest that single-stage approach requires shorter hospitalization time and is more cost-effective than the two-stage approach, even though it requires considerable training. This study aimed to evaluate the implementation of a protocol for managing concomitant choledocholithiasis and cholelithiasis using single-stage treatment. METHODS: A prospective cohort study of patients diagnosed with cholelithiasis and choledocholithiasis who were treated with the single-stage treatment - transcystic instrumentation, choledocotomy or intraoperative endoscopic retrograde cholangiopancreatography (ERCP) - between September 2010 and June 2017 was assessed. The primary outcomes were complications, hospital stay, operative time and recurrence rate. RESULTS: 164 patients were enrolled. 141 (86%) were operated laparoscopically. Preoperatively diagnosed stones were not found by intraoperative imaging or disappeared after "flushing" in 38 patients (23.2%). Surgical approach was transcystic in 45 patients (27.41%), choledochotomy in 74 (45.1%), intraoperative ERCP in 4 (2.4%), and bilioenteric derivation in 3 (1.8%). Mean hospitalization stay was 4.4 days. Mean operative time was 166 min 27 patients (16.5%) had complications and 1 patient was exitus (0.6%). Recurrence rate was 1.2%. CONCLUSIONS: Single-stage approach is a safe and effective management option for concomitant cholelithiasis and choledocolithiasis. Furthermore, a significant number of common bile duct stones pass spontaneously to duodenum or can benefit from a transcystic approach, with presumable low morbidity and cost-efficiency.

Endoscopic dilation of gastrojejunal anastomotic strictures after laparoscopic gastric bypass. Predictors of initial failure.

BACKGROUND AND AIMS: Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the most frequent technique performed in bariatric surgery. Gastrojejunal anastomotic stricture is one of the most common postoperative complications. The aims of this study were to evaluate the efficacy and safety of endoscopic balloon dilation in the treatment of the gastrojejunal anastomotic strictures after LRYGB and to look for predicting factors that would indicate the need of repeated dilations. METHODS: We included all patients with morbid obesity who underwent a LRYGB at our institution between January 2002 and July 2007. All patients who developed symptoms compatible with stricture of the gastrojejunostomy were referred to upper gastrointestinal endoscopy and underwent endoscopic balloon dilation. RESULTS: One hundred and five out of the 1,330 patients (7.8%) developed an anastomotic stricture. The mean time to diagnosis was 3 months after the surgery. The mean diameter of the stricture was 5 mm. Sixty out of the 105 patients required only one dilation (57%), 29 required two dilations (27,6%), 13 required three dilations, and 3 patients underwent a fourth dilation. Clinical success was achieved in 100% of the cases, with an average of 1.6 dilations. The statistical analysis showed that only the time from surgery to stricture formation (p = 0.007) and the diameter achieved at the first dilation (p = 0.015) had statistical significance as predictors of the need of one or more dilations. CONCLUSIONS: Endoscopic balloon dilation is a safe and effective method. Most of the patients are successfully managed with one or two dilations. The longer time from surgery to the appearance of symptoms ant the largest diameter achieved at the first dilation are the only predicting factors of success with only one dilation.

[Utility of single- and double-balloon enteroscopy]. / Utilidad de la enteroscopia de simple y de doble balón.

Single- and double-balloon enteroscopes have similar efficacy. The entire small bowel can be examined through the oral route in 60-90minutes in 25-40% of patients. Using the oral and rectal routes, complete examinations can be performed in 75% of patients The diagnostic indications are mid-gastrointestinal bleeding tumors, Crohn's disease, intestinal obstruction and atypical malabsorption. Therapeutic indications include access to enterostomy, hemostasis, foreign body withdrawal, dilatation and polypectomy in the small bowel. This procedure is also useful to place enteral feeding tubes in patients with an excluded stomach. Hemostatic efficacy is high in patients with elevated transfusional requirements. For polypectomy, this technique has not been demonstrated to have the same efficacy/risk as colonoscopy. Complications include pancreatitis (0.34%) and perforation (0.34-6.4%). The level of evidence for almost all indications is low, since few prospective and homogeneous studies have been performed.

The beneficial effects of argon plasma coagulation in the management of different types of gastric vascular ectasia lesions in patients admitted for GI hemorrhage.

BACKGROUND: Despite different forms of treatment, few studies have been performed on the outcome and prognosis of patients admitted to the hospital because of gastric vascular ectasia (GVE) and upper-GI bleeding (UGIB). There is also little knowledge on the efficacy of argon plasma coagulation (APC) in different subgroups of GVE lesions. OBJECTIVE: This study was designed to evaluate the efficacy of APC in patients admitted to the hospital with UGIB because of GVE. DESIGN: Prospective evaluation of consecutive cases of UGIB because of GVE. SETTING: Tertiary and university-affiliated hospital. PATIENTS AND INTERVENTIONS: Twenty-nine patients were included and divided into 3 subgroups: focal vascular ectasia lesions (FVE) (n = 10), portal hypertensive gastropathy (PHG) (n = 11), and gastric antral vascular ectasia (GAVE) (n = 8). Patients were followed at 3 months and every 6 months thereafter during a mean of 23.1 months (range 18-37 months). All patients received intensive APC treatment that was repeated, depending on the endoscopic appearance or clinical evaluation. RESULTS: The overall success of APC treatment was 86%, with only one recurrence of UGIB during the follow-up period. The number of APC sessions was 1.2, 2.2, and 2.3, in each subgroup (not significant), with a total number of sessions of 1.9 +/- 1.3. Treatment success was 90% in the FVE group, 81% in the PHG group, and 87.5% in the GAVE group (NS). The rise in hematocrit from baseline values in the overall group and in each subgroup was significant (P > .01). LIMITATIONS: A single-center study and small sample. CONCLUSIONS: Endoscopic thermal ablation with APC is effective in managing UGIB and in reducing transfusion requirements in patients admitted for GI hemorrhage because of different endoscopic types of GVE.

[Guidelines for the rational use of endoscopy to improve the detection of relevant lesions in an open-access endoscopy unit: a prospective study]. / Recomendaciones de utilización de la endoscopia: análisis de la probabilidad de encontrar lesiones significativas en los pacientes procedentes de la atención extrahospitalaria.

BACKGROUND AND OBJECTIVE: Almost 50% of gastrointestinal endoscopies performed in our Unit correspond to patients coming from primary care. Since resources are finite, adherence to appropriate indications for these procedures is essential. We prospectively assessed the appropriateness of gastrointestinal endoscopies referred from Primary Care according to the European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE) criteria. PATIENTS AND METHOD: From May to June 2005, all consecutive patients referred from Primary care to our unit for open-access endoscopy were included (478 colonoscopies and 264 gastroscopies). Appropriateness of each exploration was established according to the EPAGE criteria. In order to evaluate whether appropriateness of use correlated with the diagnostic yield of endoscopies, relevant endoscopic findings were recorded. RESULTS: In 146 patients (20%), an endoscopy indication was not listed in the EPAGE guidelines or data were incomplete and they were not evaluated. In the remaining 596 patients, the indication of the procedure was considered appropriate in 401 (67%) patients (253 [69%], colonoscopies and 148 [65%], gastroscopies). The diagnostic yield was significantly higher for appropriate endoscopies (30% vs 7%, p < 0.001). Endoscopies were more appropriate in older patients and in non-foreigners. CONCLUSIONS: The diagnostic yield of gastrointestinal endoscopies in patients coming from primary Care increases with the appropriateness of indications according to the EPAGE criteria. Since a noteworthy proportion of these patients' endoscopies are considered inappropriate, the implementation of validated guidelines for its appropriate use could improve this situation.

Endoscopic ultrasound-guided fine needle aspiration: predictive factors of accurate diagnosis and cost-minimization analysis of on-site pathologist.

AIMS: To evaluate a) new diagnoses by endoscopic ultrasound guided real-time fine-needle aspiration (EUS-FNA) compared with EUS alone; b) the predictive factors for an accurate EUS-FNA diagnosis, and c) the cost-effectiveness of the presence of an on-site cytopathologist. PATIENTS AND METHODS: Demographic data, ultrasonographic characteristics, technical information on EUS-FNA and cytological results were prospectively collected in 213 patients. The gold standard used was pathological examination or clinical follow-up. Operating characteristics of EUS-FNA, multivariate analysis, and a cost-minimization study of on-site evaluation were performed with these variables. RESULTS: Samples were obtained from a total of 262 lesions: extramural masses (n = 115), lymph nodes (n = 96), cysts (n = 40) and intramural lesions (n = 11). The overall accuracy of EUS-FNA was 89% (234/262 lesions). The accuracy of EUS in discriminating between malignant and benign disease was 92% but 105 lesions (40% of the total) were classified as indeterminate. The addition of FNA to EUS allowed almost all lesions (89%) to be diagnosed with an accuracy of 90%. The only variable independently associated with an incorrect diagnosis was intramural location of the target lesion. The effectiveness of EUS-FNA in the complete series progressively increased, reaching a plateau in the fourth pass. The presence of an attendant cytopathologist was cost-effective. CONCLUSIONS: EUS-FNA allows diagnosis of most lesions classified as indeterminate by EUS alone. The only factor independently associated with low accuracy is intramural location of the lesion. The availability of an on-site cytopathologist is cost-effective.

[Usefulness of endoscopic ultrasound-guided fine needle aspiration in the diagnosis of mediastinal lesions]. / Valor de la punción aspirativa con aguja fina guiada por ultrasonografía endoscópica en el diagnóstico de las lesiones mediastínicas.

OBJECTIVE: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a safe and effective technique for the diagnosis of focal pancreatic lesions and enlarged abdominal lymph nodes. The aim of this study was to assess the usefulness of EUS-FNA in the diagnosis of mediastinal lesions. PATIENTS AND METHODS: A retrospective review was performed of all consecutive cases in which EUS-FNA was used for the diagnosis of a mediastinal lesion between January 2001 and September 2003. We used a radial echoendoscope to assess the characteristics of the lesion and a linear-array echoendoscope to perform transesophageal needle aspiration with a 22-gauge needle. Histopathology of the resected specimen was considered as the gold standard in surgically treated patients whereas cytology obtained by EUS-FNA was the gold standard when surgery was not indicated. RESULTS: EUS-FNA was performed in 59 patients with a total of 89 lesions with mean (SD) dimensions of 2.4 (2.0) cm x 1.6 (1.4) cm. Malignant lesions were larger than benign ones (short axis, 2.7 [1.4] as compared with 1.0 [0.9] cm; P< .001). The diagnosis was obtained for 53 patients (90%) and 81 lesions (91%) with a mean of 2 (1) passes per lesion. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of EUS-FNA were 81%, 100%, 100%, 75%, and 88%, respectively, when analyzed by lesion, and 88%, 100%, 100%, 80%, and 92% when analyzed by patient. CONCLUSIONS: EUS-FNA is an effective technique for the diagnosis of mediastinal lesions. The likelihood of malignancy increases with size.

Transesophageal ultrasound-guided fine needle aspiration improves mediastinal staging in patients with non-small cell lung cancer and normal mediastinum on computed tomography.

The aim of the current study was to prospectively assess the value of transesophageal ultrasound-guided fine needle aspiration (EUS-FNA) in the mediastinal staging of patients with non-small cell lung cancer (NSCLC) and CT negative for lymph node (LN) metastases, candidates for surgical resection. EUS-FNA was performed using the standard technique and LNs with at least one morphological feature suggestive of malignancy were sampled. Pathological exam of surgical specimens or tumor positive cytology was used as gold standard. Forty seven patients were included, 21% of whom had advanced disease (pN2) undetected by CT. EUS-FNA demonstrated LN metastases in 50% of them (11% of the whole series), and there were no false positives, resulting in a sensitivity, specificity, positive and negative predictive values and accuracy of 50%, 100%, 100%, 88% and 89%, respectively. In conclusion, EUS-FNA improves mediastinal staging in patients with NSCLC and CT negative for mediastinal nodes. Therefore, EUS-FNA should be considered in any patient with NSCLC and no distant metastases before any therapeutic decision is taken.

Endoscopic ultrasonography in patients with large gastric folds at endoscopy and biopsies negative for malignancy: predictors of malignant disease and clinical impact.

OBJECTIVES: The aims of the study were to assess in patients with large gastric folds at endoscopy and endoscopic biopsies that tested negative for malignancy: (i) the predictive variables of malignancy in endoscopic ultrasonography (EUS), (ii) the impact of EUS. METHODS: Patients with this condition evaluated with radial EUS (following the standard study protocol of our Unit in these patients) during a 5-yr period were included. Nine variables were evaluated as possible predictors of malignancy (chi2, t-test, and logistic regression procedure) using pathology results, or a minimum of 2 yr of follow-up as gold standard. Likelihood ratios (LR), pre-EUS, and post-EUS probabilities for the diagnosis of malignancy were used to assess the clinical impact of the technique. RESULTS: Sixty-one patients were included (40 benign and 21 malignant). Predictive factors of malignancy were as follows: thickened gastric wall, thickened deep layers, impaired gastric distension, loss of the wall structure, and presence of ascites or lymph nodes, whereas the enlargement of superficial layers was a predictor of a benign condition. The enlargement of deep layers, as assessed by EUS was the only independent predictive factor for malignancy. When using this parameter, the pre-EUS probability of malignancy in our series (34%) increased up to 95% when EUS suggested malignancy (positive LR = 45), whereas it decreased to 4.7% when EUS precluded this diagnosis (negative LR = 0.102). CONCLUSIONS: (i) The enlargement of deep layers is the only independent predictive factor for malignancy in patients with large gastric folds at endoscopy and biopsies testing negative for malignancy and (ii) EUS has a high clinical impact in these patients.