CTNND1 is involved in germline predisposition to early-onset gastric cancer by affecting cell-to-cell interactions.

BACKGROUND: CDH1 and CTNNA1 remain as the main genes for hereditary gastric cancer. However, they only explain a small fraction of gastric cancer cases with suspected inherited basis. In this study, we aimed to identify new hereditary genes for early-onset gastric cancer patients (EOGC; < 50 years old). METHODS: After germline exome sequencing in 20 EOGC patients and replication of relevant findings by gene-panel sequencing in an independent cohort of 152 patients, CTNND1 stood out as an interesting candidate gene, since its protein product (p120ctn) directly interacts with E-cadherin. We proceeded with functional characterization by generating two knockout CTNND1 cellular models by gene editing and introducing the detected genetic variants using a lentiviral delivery system. We assessed ß-catenin and E-cadherin levels, cell detachment, as well as E-cadherin localization and cell-to-cell interaction by spheroid modeling. RESULTS: Three CTNND1 germline variants [c.28_29delinsCT, p.(Ala10Leu); c.1105C > T, p.(Pro369Ser); c.1537A > G, p.(Asn513Asp)] were identified in our EOGC cohorts. Cells encoding CTNND1 variants displayed altered E-cadherin levels and intercellular interactions. In addition, the p.(Pro369Ser) variant, located in a key region in the E-cadherin/p120ctn binding domain, showed E-cadherin mislocalization. CONCLUSIONS: Defects in CTNND1 could be involved in germline predisposition to gastric cancer by altering E-cadherin and, consequently, cell-to-cell interactions. In the present study, CTNND1 germline variants explained 2% (3/172) of the cases, although further studies in larger external cohorts are needed.

Jejunal gist simulating a uterine myoma: A case report.

INTRODUCTION: A small bowel gastrointestinal stromal tumor (GIST) is a rare neoplasm of the gastrointestinal tract. The manifestation of bleeding is a diagnostic challenge and could present as a life-threatening situation that needs urgent intervention. PRESENTATION OF CASE: 64-year-old woman consulted for episodes of melena and anemia. The upper and lower endoscopies were not diagnostic. Capsule endoscopy (CE) revealed a probable jejunal hemangioma, however double-balloon enteroscopy and magnetic resonance imaging (MRI) did not show any intestinal nodule but MRI show a pelvic mass apparently related to the uterus confirmed by a gynecologist. Even so, the patient returned with melena, and a contrast-enhanced computed tomography (CT) scan again identified a pelvic mass, highlighting that its vascularization drained into the superior mesenteric territory and seemed to invade the jejunum, with active bleeding, suspicious for jejunal GIST. A laparotomy was performed to remove the jejunal mass. Histopathology and immunohistochemical studies confirmed the diagnosis. DISCUSSION: Bleeding is a common symptom in small bowel GISTs but its diagnoses could be difficult because its location. In most cases, gastroscopy and colonoscopy are not useful and CE or imaging studies are necessary to find the cause of bleeding. Moreover, it has recently proved that bleeding is a prognostic risk factor because it is related to tumor rupture and tumor invasion of blood vessels. CONCLUSION: In this case, bleeding caused by small bowel GIST was misdiagnosed in endoscopic procedures and the clinical management was delayed. CT angiography was the most effective investigation to detect the source of bleeding.

Clinical, Molecular and Genetic Characteristics of Early Onset Gastric Cancer: Analysis of a Large Multicenter Study.

Gastric adenocarcinoma (GC) is a common tumor with high morbidity and mortality. Only 7% of patients with GC are diagnosed before age 50 (early onset gastric cancer (EOGC)), and their characteristics have been poorly described. We aimed to describe clinical, molecular, and genetic characteristics of EOGC. A total of 309 patients with EOGC were retrospectively studied in four Spanish centers. Personal information, family history, and tumor information were registered. Germinal genetic analysis was performed in patients who met current criteria of a hereditary syndrome at the time of diagnosis. The median age at diagnosis was 44 years. The majority (73.3%) of tumors were diffuse, and 78.3% were diagnosed in an advanced stage. Familial aggregation of GC was present in 18/117 (15.4%) cases, and 5/117 (4.3%) met criteria for familial GC. MMR-IHC was performed in 126/309 (40.7%) tumors: 4/126 (3.1%) had loss of expression in MLH1/PMS2, without an associated germline mutation. Sixteen germline genetic analyses were performed, detecting a pathogenic variant in four (25%) cases: one in BRCA2, one in TP53, and two in CDH1. Most EOGC are diffuse and diagnosed in an advanced stage. In these patients, DNA MMR system deficiency is uncommon. Although familial aggregation was observed in only 15% of cases, a germline mutation was found in 25% of patients tested with clinical criteria. This demonstrates that EOGC has a marked genetic heterogeneity, reinforcing the importance of an accurate genetic counseling and enhancing the emerging use of multigene panels.

Predictors of Metachronous Risk Polyps After Index Colonoscopy.

INTRODUCTION: Guidelines for surveillance after polypectomy are lacking in strong evidence. Our aim was to identify some precursors of colorectal cancer lesions at 3 years after polypectomy to improve stratification and surveillance programs. METHODS: We included patients with high-risk lesions (HRLs), defined as advanced adenoma (AA), large serrated polyps (SPs), and multiplicity (≥3 of any adenomas/SPs). Data on age, sex, cardiovascular risk factors, pharmacological treatment, and the histological characteristics in each individual, and mutations in genes involved in the most advanced index polyp, were collected. Parameters independently associated with a metachronous HRL diagnosis were evaluated through univariate and multivariate analyses. The results are reported as odds ratios and 95% confidence intervals along with P values. RESULTS: A total of 537 cases (median age: 60.7 years; 66% male) were included. Dyslipidemia and smoking correlated with metachronous HRLs. Multivariate logistic regression analysis showed that the presence of multiplicity with ≥3 polyps on the index colonoscopy was significantly associated with metachronous HRL, AA, proximal AA, and ≥3 polyps at 3 years. In addition, independent predictors of metachronous proximal AA were increasing age, female sex, and the loss of expression of the MLH1 protein. DISCUSSION: Multiplicity was a strong predictor of HRLs at 3 years, although the inclusion of other clinical variables (age, sex, smoking status, and dyslipidemia) improves surveillance recommendations. Without these risk factors, the surveillance could be extended to 5 years; we propose examining the somatic expression of MHL1 in all patients.

Detection of serrated lesions in proximal colon by simulated sigmoidoscopy vs faecal immunochemical testing in a multicentre, pragmatic, randomised controlled trial.

BACKGROUND: The diagnostic yield of the faecal immunochemical test and sigmoidoscopy in detecting proximal serrated polyps in a colorectal cancer screening programme has not been fully assessed. AIM: We determined the detection rate of proximal serrated polyps by simulated sigmoidoscopy and faecal immunochemical test compared with total colonoscopy in a population-based, multicentre, nationwide, randomised controlled trial (ColonPrev study). METHODS: Sigmoidoscopy yield was simulated based on the UK-Flexible Sigmoidoscopy Trial for total colonoscopy referral. Definitions were: proximal serrated polyp (proximal serrated polyp): sessile serrated polyp or hyperplastic polyp of any size and proximal at-risk serrated polyp (at-risk proximal serrated polyp): sessile serrated polyp of any size or hyperplastic polyp ≥ 10 mm, both located proximally to the splenic flexure. RESULTS: A total of 10,611 individuals underwent faecal immunochemical test and 5059 underwent total colonoscopy and were evaluated by simulated sigmoidoscopy. Sigmoidoscopy and faecal immunochemical test were less accurate in detecting proximal serrated polyps (odds ratio: 0.13; 95% confidence interval: 0.10-0.18 and 0.13; 0.09-0.18, p < 0.0001, respectively). Both tests were inferior to colonoscopy in detecting at-risk proximal serrated polyps, and sigmoidoscopy was inferior to faecal immunochemical test in detecting these lesions (odds ratio: 0.17; 95% confidence interval: 0.10-0.30 and 0.25; 0.17-0.37, p < 0.0001, respectively). CONCLUSION: Sigmoidoscopy and faecal immunochemical test are less accurate in detecting proximal serrated polyps than colonoscopy, particularly in women.

Efficacy of a multifactorial strategy for bowel preparation in diabetic patients undergoing colonoscopy: a randomized trial.

Background and study aims: Previous studies have reported that diabetes mellitus is an independent risk factor for inadequate bowel preparation. Current guidelines do not recommend a specific preparation for this patient population. The aims of this study were to assess the efficacy, safety, and tolerability of an adapted preparation protocol for colon cleansing in patients with type 2 diabetes mellitus. Patients and methods: This randomized, single-blind, parallel group, superiority trial compared a conventional bowel preparation protocol (CBP) with a diabetes-specific preparation protocol (DSP). The CBP included a low-fiber diet for 3 days followed by a clear liquid diet for 24 hours before colonoscopy. The DSP included a multifactorial strategy combining an educational intervention, a low-fiber diet, and adjustment of blood glucose-lowering agents. All patients received 4 L of a polyethylene glycol solution in a split-dose regimen. The endoscopists were blinded to the preparation protocol. The primary outcome measure was inadequate bowel preparation according to the Boston Bowel Preparation Scale. Secondary outcome measures included hypoglycemic events, tolerability, and acceptability. Results: A total of 150 patients were included in the study (74 CBP and 76 DSP). Both groups were comparable in terms of baseline characteristics. Inadequate bowel cleansing was more frequent following CBP than DSP (20 % vs. 7 %, P = 0.014; risk ratio 3.1, 95 % confidence interval 1.2 - 8). Only CBP and performance status were independently associated with inadequate bowel preparation. Both preparations were equally tolerated and accepted by patients, and side-effects were similar between the groups. Conclusions: A multifactorial strategy for bowel preparation in patients with diabetes undergoing colonoscopy showed a threefold reduction in the rate of inadequate bowel preparation, with no differences in safety and tolerability compared with conventional preparation. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02300779).