Digital imaging software versus the "eyeball" method in quantifying steatosis in a liver biopsy.

Steatotic livers represent a potentially underutilized resource to increase the donor graft pool; however, 1 barrier to the increased utilization of such grafts is the heterogeneity in the definition and the measurement of macrovesicular steatosis (MaS). Digital imaging software (DIS) may better standardize definitions to study posttransplant outcomes. Using HALO, a DIS, we analyzed 63 liver biopsies, from 3 transplant centers, transplanted between 2016 and 2018, and compared macrovesicular steatosis percentage (%MaS) as estimated by transplant center, donor hospital, and DIS. We also quantified the relationship between DIS characteristics and posttransplant outcomes using log-linear regression for peak aspartate aminotransferase, peak alanine aminotransferase, and total bilirubin on postoperative day 7, as well as logistic regression for early allograft dysfunction. Transplant centers and donor hospitals overestimated %MaS compared with DIS, with better agreement at lower %MaS and less agreement for higher %MaS. No DIS analyzed liver biopsies were calculated to be >20% %MaS; however, 40% of liver biopsies read by transplant center pathologists were read to be >30%. Percent MaS read by HALO was positively associated with peak aspartate aminotransferase (regression coefficient= 1.04 1.08 1.12 , p <0.001), peak alanine aminotransferase (regression coefficient = 1.04 1.08 1.12 , p <0.001), and early allograft dysfunction (OR= 1.10 1.40 1.78 , p =0.006). There was no association between HALO %MaS and total bilirubin on postoperative day 7 (regression coefficient = 0.99 1.01 1.04 , p =0.3). DIS provides reproducible quantification of steatosis that could standardize MaS definitions and identify phenotypes associated with good clinical outcomes to increase the utilization of steatite livers.

The number of microspheres in Y90 radioembolization directly affects normal tissue radiation exposure.

PURPOSE: In Y90 radioembolization, the number of microspheres infused varies by more than a factor of 20 over the shelf-life of the glass radioembolization device. We investigated the effect of the number of Y90 microspheres on normal liver tissue. METHOD: Healthy pigs received lobar radioembolization with glass Y90 microspheres at 4, 8, 12, and 16 days post-calibration, representing a > 20× range in the number of microspheres deposited per milliliter in tissue. Animals were survived for 1-month post-treatment and the livers were explanted and scanned on a micro CT system to fully characterize the microscopic distribution of individual microspheres. A complete 3D microdosimetric evaluation of each liver was performed with a spatially correlated analysis of histopathologic effect. RESULTS: Through whole-lobe microscopic identification of each microsphere, a consistent number of microspheres per sphere cluster was found at 4, 8, and 12 days postcalibration, despite an 8-fold increase in total microspheres infused from days 4 to 12. The additional microspheres instead resulted in more clusters formed and, therefore, a more homogeneous microscopic absorbed dose. The increased absorbed-dose homogeneity resulted in a greater volume fraction of the liver receiving a potentially toxic absorbed dose based on radiobiologic models. Histopathologic findings in the animals support a possible increase in normal liver toxicity in later treatments with more spheres (i.e., ≥ day 12) compared to early treatments with less spheres (i.e., ≤ day 8). CONCLUSION: The microdosimetric evidence presented supports a recommendation of caution when treating large volumes (e.g., right lobe) using glass 90Y microspheres at more than 8 days post-calibration, i.e., after "2nd week" Monday. The favorable normal tissue microscopic distribution and associated low toxicity of first week therapies may encourage opportunities for dose escalation with glass microspheres and could also be considered for patients with decreased hepatic reserve.

Stylet slow-pull versus standard suction for endoscopic ultrasound-guided fine-needle aspiration of solid pancreatic lesions: a multicenter randomized trial.

BACKGROUND AND STUDY AIM: Standard endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) procedures involve use of no-suction or suction aspiration techniques. A new aspiration method, the stylet slow-pull technique, involves slow withdrawal of the needle stylet to create minimum negative pressure. The aim of this study was to compare the sensitivity of EUS-FNA using stylet slow-pull or suction techniques for malignant solid pancreatic lesions using a standard 22-gauge needle. PATIENTS AND METHODS: Consecutive patients presenting for EUS-FNA of pancreatic mass lesions were randomized to the stylet slow-pull or suction techniques using a 22-gauge needle. Both techniques were standardized for each pass until an adequate specimen was obtained, as determined by rapid on-site cytology examination. Patients were crossed over to the alternative technique after four nondiagnostic passes. RESULTS: Of 147 patients screened, 121 (mean age 64 ±â€Š13.8 years) met inclusion criteria and were randomized to the stylet slow-pull technique (n = 61) or the suction technique (n = 60). Technical success rates were 96.7 % and 98.3 % in the slow-pull and suction groups, respectively (P > 0.99). The sensitivity for malignancy of EUS-FNA was 82 % in the slow-pull group and 69 % in the suction group (P = 0.10). The first-pass diagnostic rate (42.6 % vs. 38.3 %; P = 0.71), acquisition of core tissue (60.6 % vs. 46.7 %; P = 0.14), and the median (range) number of passes to diagnosis (2 1 2 3 vs. 1 1 2; P = 0.71) were similar in the slow-pull and suction groups, respectively. CONCLUSIONS: The stylet slow-pull and suction techniques both offered high and comparable diagnostic sensitivity with a mean of 2 passes required for diagnosis of solid pancreatic lesions. The endosonographer may choose either technique during FNA.

Comprehensive analysis of efficacy and safety of peroral endoscopic myotomy performed by a gastroenterologist in the endoscopy unit: a single-center experience.

BACKGROUND AND AIMS: The safety and efficacy of peroral endoscopic myotomy (POEM) when performed by gastroenterologists in the endoscopy unit are currently unknown. The aims of this study were to assess (1) the safety and efficacy of POEM in which all procedures were performed by 1 gastroenterologist in the endoscopy unit, and (2) the predictors of adverse events and nonresponse. METHODS: All consecutive patients who underwent POEM at 1 tertiary center were included. Clinical response was defined by a decrease in the Eckardt score to 3 or lower. Adverse events were graded according to the American Society for Gastrointestinal Endoscopy lexicon's severity grading system. RESULTS: A total of 60 consecutive patients underwent POEM in the endoscopy suite with a mean procedure length of 99 minutes. The mean length of submucosal tunnel was 14 cm and the mean myotomy length was 11 cm. The median length of hospital stay was 1 day. Among 52 patients with a mean follow-up period of 118 days (range 30-750), clinical response was observed in 48 patients (92.3%). There was a significant decrease in Eckardt score after POEM (8 vs 1.19, P < .0001). The mean lower esophageal sphincter pressure decreased significantly after POEM (29 mm Hg vs 11 mm Hg, P < .0001). A total of 10 adverse events occurred in 10 patients (16.7%): 7 rated as mild, 3 as moderate, and none as severe. Procedure length was the only predictor of adverse events (P = .01). pH impedance testing was completed in 25 patients, and 22 (88%) had abnormal acid exposure, but positive symptom correlation was present in only 6 patients. All patients with symptomatic reflux were successfully treated with proton pump inhibitors. CONCLUSIONS: POEM can be effectively and safely performed by experienced gastroenterologists at a tertiary care endoscopy unit. Adverse events are infrequent, and most can be managed intraprocedurally. Post-POEM reflux is frequent but can be successfully managed medically.

Endoscopic suturing for the prevention of stent migration in benign upper gastrointestinal conditions: a comparative multicenter study.

BACKGROUND AND STUDY AIMS: Fully covered self-expandable metal stents (FCSEMSs) have increasingly been used in benign upper gastrointestinal (UGI) conditions; however, stent migration remains a major limitation. Endoscopic suture fixation (ESF) may prevent stent migration. The aims of this study were to compare the frequency of stent migration in patients who received endoscopic suturing for stent fixation (ESF group) compared with those who did not (NSF group) and to assess the impact of ESF on clinical outcome. PATIENTS AND METHODS: This was a retrospective study of patients who underwent FCSEMS placement for benign UGI diseases. Patients were divided into either the NSF or ESF group. Outcome variables, including stent migration, clinical success (resolution of underlying pathology), and adverse events, were compared. RESULTS: A total of 125 patients (44 in ESF group, 81 in NSF group; 56 benign strictures, 69 leaks/fistulas/perforations) underwent 224 stenting procedures. Stent migration was significantly more common in the NSF group (33 % vs. 16 %; P = 0.03). Time to stent migration was longer in the ESF group (P = 0.02). ESF appeared to protect against stent migration in patients with a history of stent migration (adjusted odds ratio [OR] 0.09; P = 0.002). ESF was also significantly associated with a higher rate of clinical success (60 % vs. 38 %; P = 0.03). Rates of adverse events were similar between the two groups. CONCLUSIONS: Endoscopic suturing for stent fixation is safe and associated with a decreased migration rate, particularly in patients with a prior history of stent migration. It may also improve clinical response, likely because of the reduction in stent migration.

Intraoperative measurement of esophagogastric junction cross-sectional area by impedance planimetry correlates with clinical outcomes of peroral endoscopic myotomy for achalasia: a multicenter study.

BACKGROUND: Peroral endoscopic myotomy (POEM) has been introduced as an endoscopic alternative to surgical myotomy. The endoluminal functional lumen imaging probe (endoFLIP) evaluates esophagogastric junction (EGJ) distensibility based on cross-sectional area and pressure in response to volume distension. The aim of this study was to evaluate whether there is a correlation between endoFLIP measurements during POEM and postoperative clinical outcomes in terms of symptom relief and development of post-procedure reflux. METHODS: We conducted a retrospective review of achalasia patients who underwent POEM and intraoperative endoFLIP at three tertiary centers. Patients were divided into two groups based on clinical response measured by Eckardt score (ES): good response (ES < 3) or poor response (ES ≥ 3). Post-procedure reflux was defined as the presence of esophagitis and/or abnormal pH study. EGJ diameter, cross-sectional area, and distensibility measured by endoFLIP were compared. RESULTS: Of the 63 treated patients, 50 had good and 13 had poor clinical response. The intraoperative final EGJ cross-sectional area was significantly higher in the good-response group versus poor-response group; median (interquartile range): 89.0 (78.5-106.7) versus 72.4 (48.8-80.0) mm(2) [p = 0.01]. The final EGJ cross-sectional area was also significantly higher in patients who had reflux esophagitis after POEM: 99.5 (91.2-103.7) versus 79.3 (57.1-94.2) mm(2) [p = 0.02]. CONCLUSION: Intraoperative EGJ cross-sectional area during POEM for achalasia correlated with clinical response and post-procedure reflux. Impedance planimetry is a potentially important tool to guide the extent and adequacy of myotomy during POEM.

Intraprocedural fluoroscopy to determine the extent of the cardiomyotomy during per-oral endoscopic myotomy (with video).

BACKGROUND: An adequate myotomy on the gastric side is considered essential to optimize outcomes in patients undergoing per-oral endoscopic myotomy (POEM). An objective method to measure the length of gastric myotomy has not yet been reported. OBJECTIVE: To evaluate a new method of precisely determining the length of the submucosal tunnel below the esophagogastric junction (EGJ) using intraprocedural fluoroscopy. DESIGN: Single-center cohort study. SETTING: Academic tertiary care center. PATIENTS: Twenty-four consecutive patients who underwent POEM for management of achalasia. INTERVENTIONS: A radiopaque marker (endoscopic clip placed at the EGJ or fluoroscopically guided placement of a 19-gauge needle on the skin) was used to mark the EGJ. The endoscope was inserted to the most distal aspect of the submucosal tunnel and, using fluoroscopy, the distance between the radiopaque marker and the tip of the endoscope was measured. MAIN OUTCOME MEASUREMENTS: Technical success, procedural impact, duration of technique, and adverse events. RESULTS: Technical success was achieved in 100% of patients. The submucosal tunnel was extended in 5 patients (20.8%) with a mean extension of 1.4±.5 cm. The mean increase in procedure time was 4 minutes with the endoscopic clip and 2 minutes with the 19-gauge needle. There were no adverse events associated with this technique. LIMITATIONS: Need for fluoroscopy. Absence of available criterion standard. CONCLUSIONS: Intraprocedural fluoroscopy was an efficient and safe method of objectively documenting the extent of gastric myotomy during POEM. This may benefit those investigating the anatomic and physiologic changes that occur during the myotomy and those early in their experience performing POEM.

Refractory gastroparesis can be successfully managed with endoscopic transpyloric stent placement and fixation (with video).

BACKGROUND AND AIMS: Medical treatment options for gastroparesis are limited. Data from studies of botulinum toxin and surgical pyloroplasty suggest that disruption of the pylorus can result in symptomatic improvement in some patients with refractory gastroparetic symptoms. The aim of this study was to determine the clinical response to transpyloric stent (TPS) placement in patients with gastroparetic symptoms refractory to standard therapy. METHODS: Patients with gastroparesis refractory to medical treatment were referred for TPS placement for salvage therapy. Self-reported symptom improvement, stent migration rate, and pre- and post-stent gastric-emptying study results were collected. RESULTS: A total of 30 patients with refractory gastroparesis underwent 48 TPS procedures. Of these, 25 of 48 (52.1%) were performed in patients admitted to the hospital with intractable gastroparetic symptoms. Successful stent placement in the desired location across the pylorus (technical success) was achieved during 47 procedures (98%). Most (n = 24) stents were anchored to the gastric wall by using endoscopic suturing with a mean number of sutures of 2 (range 1-3) per procedure. Clinical response was observed in 75% of patients, and all inpatients were successfully discharged. Clinical success in patients with the predominant symptoms of nausea and vomiting was higher than in those patients with a predominant symptom of pain (79% vs 21%, P = .12). A repeat gastric-emptying study was performed in 16 patients, and the mean 4-hour gastric emptying normalized in 6 patients and significantly improved in 5 patients. Stent migration was least common (48%) when stents were sutured. CONCLUSION: TPS placement is a feasible novel endoscopic treatment modality for gastroparesis and improves both symptoms and gastric emptying in patients who are refractory to medical treatment, especially those with nausea and vomiting. TPS placement may be considered as salvage therapy for inpatients with intractable symptoms or potentially as a method to select patients who may respond to more permanent therapies directed at the pylorus.

Intraoperative determination of the adequacy of myotomy length during peroral endoscopic myotomy (POEM): the double-endoscope transillumination for extent confirmation technique (DETECT).

BACKGROUND AND STUDY AIMS: Precise identification of the gastroesophageal junction (GEJ) is a challenging prerequisite for adequate length of an esophageal myotomy. Multiple standard methods to identify the GEJ have been described; however, a more objective modality is needed to ensure effective peroral endoscopic myotomy (POEM). PATIENTS AND METHODS: In the double-endoscope transillumination for extent confirmation technique (DETECT), an ultraslim gastroscope is passed to the most distal aspect of the submucosal tunnel created during POEM. A regular gastroscope is advanced into the stomach, and the visualization of transillumination from the ultraslim gastroscope enables identification of the extent of the submucosal tunnel. RESULTS: A total of 10 patients underwent POEM with DETECT. Initial submucosal tunneling was performed based on a determination of the GEJ location via standard methods. DETECT indicated the tunnel extent to be inadequate in 50% of patients, and the tunnel was extended a further 1 to 2cm. The mean initial tunnel length was 15.4cm, with a mean initial myotomy length of 11.9cm. DETECT was performed in less than 10 minutes without complications. CONCLUSION: DETECT is an objective method for determining the adequacy of the submucosal tunnel length during POEM.

An unusual case of carcinoma with mesonephric-like features with a spindle cell component diagnosed on the Pap test of the uterine cervix: Cytomorphologic and immunophenotypic features and diagnostic pitfalls.

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms arising in the cervix, endometrium, and ovary. In contrast to mesonephric carcinomas (MC), mesonephric-like adenocarcinomas are not associated with mesonephric remnants. Both entities have a similar appearance with regards to varying histomorphology patterns, including glandular, tubular, spindled, solid, and papillary, and have a specific immunophenotype and molecular features. We present a case of a 54-year-old HPV-negative woman with a Pap test that exhibits high-grade malignancy. The cell block displayed malignant cells with positive stains for PAX8, GATA3, and TTF1 by immunohistochemistry. The diagnosis of adenocarcinoma with mesonephric like features was rendered. MLA can be challenging on the small specimens and often misinterpreted as other endometrial neoplasms. Furthermore, the accurate diagnosis carries a well-described risk of aggressive clinical behavior.

Gastric Mucosal Devitalization (GMD): Using the Porcine Model to Develop a Novel Endoscopic Bariatric Approach.

BACKGROUND AND AIMS: As the pig model has similar gastrointestinal anatomy and physiology to humans, we used pigs to create a gastric mucosal devitalization (GMD) model in preparation for clinical translation of this technique as an endoscopic bariatric therapy (EBT). The aims of this study were to determine the ablation parameters and technique for a successful, safe, and feasible large surface area GMD that produces weight loss. METHODS: We performed GMD using argon plasma coagulation (APC) in 3 phases. Phase 1 assessed the ablation energy required to accomplish selective mucosal ablation using ex vivo pig stomachs (n = 2). Phase 2 assessed the optimal percentage of mucosal surface area to be treated and was performed on 10 pigs. Phase 3 assessed feasibility, efficacy, and safety with 8 pigs randomized into GMD (n = 4) or sham (SH, n = 4) and survived for 1 month. Body weights (GMD, n = 4, SH, n = 4) were measured daily in phase 3 for 1 month, and relative body weights were calculated and analyzed using one-tailed Student's t-test. Percent body fat was compared between GMD and SH at baseline and 1 month post-GMD. RESULTS: Phase 1 identified the optimal ablation parameters (120 W) that were then used in phase 2. Phase 2 revealed a trend that was suggestive that the optimal percent surface area to ablate was similar to that which is removed at laparoscopic sleeve gastrectomy. In phase 3, GMD was performed over 70% surface area of the greater curvature of the stomach in four pigs. GMD pigs had significantly lower relative body weight increase compared to SH at 1 month (1.375 ± 0.085 vs 1.575 ± 0.047, p = 0.0435). MRI showed a significantly lower body fat mass at 1 month in GMD pigs (5.9 ± 0.4% vs 12.7 ± 2.3%, p = 0.026) compared to SH. CONCLUSIONS: GMD resulted in decreased weight gain in the GMD group as evidenced by a lower relative body weight at 1 month. GMD in an animal model appears to show promise as a potential weight loss therapy.

A 52-Year-Old Man With Chest Pain and Dyspnea.

CASE PRESENTATION: A 52-year-old man came to the cardiac surgery clinic for pulmonary thromboendarterectomy (PTE) evaluation. He had initially appeared at an outside hospital 1 year earlier, with chest pain and shortness of breath. He had no known chronic conditions. A CT pulmonary angiogram (CTPA) at that time showed a filling defect at the bifurcation of the main pulmonary artery. A transthoracic echocardiogram revealed mild mitral valve regurgitation, but otherwise the results were normal. As he was hemodynamically stable and not hypoxemic, he was treated solely by anticoagulation. Despite adhering to prescribed apixaban, he developed progressive dyspnea and reduced exercise tolerance over the subsequent year. A repeat CTPA performed 12 months after the initial presentation showed a persistent filling defect at the level of the pulmonary artery bifurcation, with a new extension now completely occluding the right main pulmonary artery. A pulmonary angiogram confirmed this complete occlusion, and right heart catheterization revealed precapillary pulmonary hypertension, with a mean pulmonary artery pressure of 50 mm Hg. His anticoagulation was transitioned to enoxaparin for presumed apixaban treatment failure, and an investigation for hypercoagulable conditions was initiated. His lupus anticoagulant test result was positive, but he did not meet the criteria for antiphospholipid syndrome because he was negative for anticardiolipin and ß2-glycoprotein antibodies. Assays for antithrombin III, protein C, prothrombin gene, and factor V Leiden mutations produced normal results.

LIN28B induces a differentiation program through CDX2 in colon cancer.

Most colorectal cancers (CRCs) are moderately differentiated or well differentiated, a status that is preserved even in metastatic tumors. However, the molecular mechanisms underlying CRC differentiation remain to be elucidated. Herein, we unravel a potentially novel posttranscriptional regulatory mechanism via a LIN28B/CDX2 signaling axis that plays a critical role in mediating CRC differentiation. Owing to a large number of mRNA targets, the mRNA-binding protein LIN28B has diverse functions in development, metabolism, tissue regeneration, and tumorigenesis. Our RNA-binding protein IP (RIP) assay revealed that LIN28B directly binds CDX2 mRNA, which is a pivotal homeobox transcription factor in normal intestinal epithelial cell identity and differentiation. Furthermore, LIN28B overexpression resulted in enhanced CDX2 expression to promote differentiation in subcutaneous xenograft tumors generated from CRC cells and metastatic tumor colonization through mesenchymal-epithelial transition in CRC liver metastasis mouse models. A ChIP sequence for CDX2 identified α-methylacyl-CoA racemase (AMACR) as a potentially novel transcriptional target of CDX2 in the context of LIN28B overexpression. We also found that AMACR enhanced intestinal alkaline phosphatase activity, which is known as a key component of intestinal differentiation, through the upregulation of butyric acid. Overall, we demonstrated that LIN28B promotes CRC differentiation through the CDX2/AMACR axis.

G-protein coupled receptor 35 (GPR35) regulates the colonic epithelial cell response to enterotoxigenic Bacteroides fragilis.

G protein-coupled receptor (GPR)35 is highly expressed in the gastro-intestinal tract, predominantly in colon epithelial cells (CEC), and has been associated with inflammatory bowel diseases (IBD), suggesting a role in gastrointestinal inflammation. The enterotoxigenic Bacteroides fragilis (ETBF) toxin (BFT) is an important virulence factor causing gut inflammation in humans and animal models. We identified that BFT signals through GPR35. Blocking GPR35 function in CECs using the GPR35 antagonist ML145, in conjunction with shRNA knock-down and CRISPRcas-mediated knock-out, resulted in reduced CEC-response to BFT as measured by E-cadherin cleavage, beta-arrestin recruitment and IL-8 secretion. Importantly, GPR35 is required for the rapid onset of ETBF-induced colitis in mouse models. GPR35-deficient mice showed reduced death and disease severity compared to wild-type C57Bl6 mice. Our data support a role for GPR35 in the CEC and mucosal response to BFT and underscore the importance of this molecule for sensing ETBF in the colon.

Phase I Study of Entinostat and Nivolumab with or without Ipilimumab in Advanced Solid Tumors (ETCTN-9844).

PURPOSE: Epigenetic modulators improve immune checkpoint inhibitor (ICI) efficacy and increase CD8+ effector:FoxP3+ regulatory T cell ratios in preclinical models. We conducted a multicenter phase I clinical trial combining the histone deacetylase inhibitor entinostat with nivolumab ± ipilimumab in advanced solid tumors. PATIENTS AND METHODS: Patients received an entinostat run-in (5 mg, weekly × 2) prior to the addition of ICIs. Dose escalation followed a modified 3+3 design [dose level (DL)1/2: entinostat + nivolumab; DL 3/4: entinostat + nivolumab + ipilimumab]. Blood and tissue samples were collected at baseline, after entinostat run-in, and after 8 weeks of combination therapy. Primary endpoints included safety and tolerability, and the recommended phase II dose (RP2D). Secondary endpoints included antitumor activity and change in tumor CD8/FoxP3 ratio pre- and post-therapy. RESULTS: Thirty-three patients were treated across four dose levels. Treatment-related adverse events (AE) included fatigue (65%), nausea (41%), anemia (38%), diarrhea (26%), and anorexia (26%). Grade 3/4 AEs included fatigue (n = 7, 21%), anemia (n = 9, 27%), and neutropenia (n = 4, 12%). The RP2D was 3 mg entinostat weekly, 3 mg/kg every 2 weeks nivolumab, and 1 mg/kg every 6 weeks ipilimumab (max four doses). The objective response rate by RECIST 1.1 was 16%, including a complete response in triple-negative breast cancer. A statistically significant increase in CD8/FoxP3 ratio was seen following the addition of ICIs to entinostat, but not post-entinostat alone. CONCLUSIONS: The combination of entinostat with nivolumab ± ipilimumab was safe and tolerable with expected rates of immune-related AEs. Preliminary evidence of both clinical efficacy and immune modulation supports further investigation.

Bacterial-Driven Inflammation and Mutant BRAF Expression Combine to Promote Murine Colon Tumorigenesis That Is Sensitive to Immune Checkpoint Therapy.

Colorectal cancer is multifaceted, with subtypes defined by genetic, histologic, and immunologic features that are potentially influenced by inflammation, mutagens, and/or microbiota. Colorectal cancers with activating mutations in BRAF are associated with distinct clinical characteristics, although the pathogenesis is not well understood. The Wnt-driven multiple intestinal neoplasia (MinApcΔ716/+) enterotoxigenic Bacteroides fragilis (ETBF) murine model is characterized by IL17-dependent, distal colon adenomas. Herein, we report that the addition of the BRAF V600E mutation to this model results in the emergence of a distinct locus of midcolon tumors. In ETBF-colonized BRAF V600E Lgr5 CreMin (BLM) mice, tumors have similarities to human BRAF V600E tumors, including histology, CpG island DNA hypermethylation, and immune signatures. In comparison to Min ETBF tumors, BLM ETBF tumors are infiltrated by CD8+ T cells, express IFNγ signatures, and are sensitive to anti-PD-L1 treatment. These results provide direct evidence for critical roles of host genetic and microbiota interactions in colorectal cancer pathogenesis and sensitivity to immunotherapy. SIGNIFICANCE: Colorectal cancers with BRAF mutations have distinct characteristics. We present evidence of specific colorectal cancer gene-microbial interactions in which colonization with toxigenic bacteria drives tumorigenesis in BRAF V600E Lgr5 CreMin mice, wherein tumors phenocopy aspects of human BRAF-mutated tumors and have a distinct IFNγ-dominant immune microenvironment uniquely responsive to immune checkpoint blockade.This article is highlighted in the In This Issue feature, p. 1601.

Evaluation of Peritumoral Fibrosis in Metastatic Colorectal Adenocarcinoma to the Liver Using Digital Image Analysis.

Objectives: It is challenging to separate peritumoral fibrosis from fibrosis due to chronic liver disease in mass-directed liver biopsies. We evaluated the distance that peritumoral fibrosis extends from metastatic colorectal adenocarcinoma in liver. Methods: Peritumoral and distant uninvolved liver trichrome stains from 25 cases were analyzed using digital image analysis. Fibrosis was quantitated at concentric intervals from each tumor and in uninvolved liver. Results: There was a 3.9 fold (range 0.9-18.6) median increase in fibrosis in the first 0.5 mm of peritumoral liver compared to distant liver. Fibrosis levels returned to baseline at median 2.5 mm (interquartile range 1.5-5.0 mm) from tumor. Conclusions: Fibrosis is markedly increased in peritumoral liver. Fibrosis levels returned to baseline by 5 mm from tumor in approximately 75% of cases. Pathologists should be cautious of fibrosis in mass-directed liver biopsies without at least 5 mm of liver tissue distal to the mass.

Does Etiology of Pancreatitis Matter? Differences in Outcomes Among Patients With Post-Endoscopic Retrograde Cholangiopancreatography, Acute Biliary, and Alcoholic Pancreatitis.

OBJECTIVES: We compared outcomes of acute alcoholic pancreatitis (AAP), acute biliary pancreatitis (ABP), and post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP). METHODS: This was a retrospective cohort study conducted at a tertiary care center between June 2007 and June 2012. RESULTS: A total of 300 (68%) patients were diagnosed with AAP, 88 (20%) with ABP, and 55 (12%) with PEP. Longer length of hospital stay (LOHS) was more common in ABP (23%) as compared with AAP (10%) and PEP (7%, P = 0.025). Pseudocyst (P = 0.048), organ failure (OF) (P = 0.01), need for interventions (P ≤ 0.001), and mortality (P = 0.002) occurred more in ABP as compared with other groups. Systemic inflammatory response syndrome was associated with LOHS of more than 10 days (P = 0.01) and multi-OF (P = 0.05). Chronic pancreatitis was associated more with pseudocyst (P < 0.001) and mortality (P = 0.03). Serum urea nitrogen of greater than 25 g/dL predicted LOHS of more than 10 days (P = 0.02), OF (P < 0.001), multi-OF (P < 0.001), and persistent OF (P < 0.001). CONCLUSIONS: Acute biliary pancreatitis is a more severe disease compared with PEP and AAP. Chronic pancreatitis, systemic inflammatory response syndrome, and high serum urea nitrogen are important predictors of morbidity.