[Results of Endoscopic Screening and Therapy of the Duodenum in MUTYH-associated Polyposis]. / Ergebnisse der endoskopischen Vorsorge und Therapie des Duodenums bei MUTYH-assoziierter Polyposis.

MUTYH-associated polyposis (MAP) is a very rare autosomal recessive polyposis syndrome. It is caused by a homozygous or compound heterozygous germline mutation in the MUTYH gene. MAP is characterised by numerous colorectal adenomas; furthermore there is an increased risk for colorectal cancer (CRC). However, the phenotype can be highly variable; for example, affected individuals also have an increased risk of polyps of the upper gastrointestinal tract and development of duodenal carcinomas.This study included 15 patients with evidence of a pathogenic MUTYH variant, who were screened at the National Center for Hereditary Tumor Syndromes. Oesophagogastroduodenoscopy (EGD) results were prospectively recorded in a database from 2012 to 2023.At least one EGD (median 4, range 1-15) was performed in 15 patients, seven of whom carried a homozygous and 8 a compound heterozygous pathogenic MUTYH variant. The median surveillance period was 115 months (range, 3-215 months). The median age at baseline was 44 (range 17-65) years. A total of 72 EGDs were performed (median 4; range 1-15). Five patients had duodenal adenomas; histology showed tubular adenomas with low grade intraepithelial dysplasia (LGIEN) in all of these cases. The total number of duodenal adenomas detected was 48, and the median number was 3 (range, 1-37). Neither high grade intraepithelial neoplasia (HGIEN) nor duodenal cancer was detected during the surveillance period.Patients with MUTYH-associated polyposis should be managed in a multidisciplinary centre for hereditary tumour disease. Our cohort showed more patients with duodenal adenomas than in previously published data. However, no progression to HGIEN or duodenal carcinomas was observed as a result of the endoscopic therapy performed.

Value of upper gastrointestinal endoscopy for gastric cancer surveillance in patients with Lynch syndrome.

In our study, we evaluated the effectiveness of upper gastrointestinal (GI) endoscopy as an instrument for early gastric cancer (GC) detection in Lynch syndrome (LS) patients by analyzing data from the registry of the German Consortium for Familial Intestinal Cancer. In a prospective, multicenter cohort study, 1128 out of 2009 registered individuals with confirmed LS underwent 5176 upper GI endoscopies. Compliance was good since 77.6% of upper GI endoscopies were completed within the recommended interval of 1 to 3 years. Forty-nine GC events were observed in 47 patients. MLH1 (n = 21) and MSH2 (n = 24) mutations were the most prevalent. GCs in patients undergoing regular surveillance were diagnosed significantly more often in an early-stage disease (UICC I) than GCs detected through symptoms (83% vs 25%; P = .0231). Thirty-two (68%) patients had a negative family history of GC. The median age at diagnosis was 51 years (range 28-66). Of all GC patients, 13 were diagnosed at an age younger than 45. Our study supports the recommendation of regular upper GI endoscopy surveillance for LS patients beginning no later than at the age of 30.

[Outcomes after Prophylactic Total Gastrectomy for Hereditary Diffuse Gastric Cancer]. / Ergebnisse nach prophylaktischer totaler Gastrektomie bei erblichem diffusem Magenkrebs.

INTRODUCTION: Prophylactic total gastrectomy is the treatment of choice in patients with germline mutation in the CDH1 gene and therefore high risk for hereditary diffuse gastric cancer (HDGC). Minimally invasive techniques have been established in recent years for treatment of gastric cancer. METHODS: We report findings with 12 patients with proven CDH1 mutation who underwent multidisciplinary treatment between 2013 and 3/2018 in our centre for hereditary tumour diseases, followed by prophylactic total gastrectomy in our department. Data were collected in a prospective hereditary tumour database. RESULTS: Open prophylactic total gastrectomy was performed in 5 patients (between 2013 and 2015) and minimally invasive prospective gastrectomy in 7 patients (between 2015 and 2018). The median age of all patients (7 women and 5 men) was 42 (range: 19 - 60) years. The mean operation time was 291 ± 72 minutes (open: 269 ± 70; minimally invasive: 307 ± 75). Perioperative 60-day mortality and anastomotic leakage rate were 0%. In 3 patients, postoperative complications occurred (according to the Clavien-Dindo classification: one each of grades II, IIIa and IVb, respectively), and therefore 25% morbidity. The average postoperative hospital stay was 14.5 ± 6.2 days (open: 16.2 ± 7.9; minimally invasive: 13.3 ± 5.0). In 10 of 12 patients (83%), foci of intramucosal signet ring cell carcinomas were found in the gastric specimen, in 9 patients with multifocal dissemination. There were no cases with advanced carcinomas (≥ pT1b) or lymph node metastases. CONCLUSION: Patients with suspected high risk for hereditary diffuse gastric cancer should be cared for in a multidisciplinary centre for hereditary tumour diseases. Laparoscopic total gastrectomy is a safe and feasible risk-reducing procedure for patients with CDH1 germline mutation. Therefore, in the absence of contraindications and with available surgical expertise, the minimally invasive operation should be the standard procedure for these patients.

Genomic and transcriptomic heterogeneity of colorectal tumours arising in Lynch syndrome.

Colorectal cancer (CRC) arising in Lynch syndrome (LS) comprises tumours with constitutional mutations in DNA mismatch repair genes. There is still a lack of whole-genome and transcriptome studies of LS-CRC to address questions about similarities and differences in mutation and gene expression characteristics between LS-CRC and sporadic CRC, about the molecular heterogeneity of LS-CRC, and about specific mechanisms of LS-CRC genesis linked to dysfunctional mismatch repair in LS colonic mucosa and the possible role of immune editing. Here, we provide a first molecular characterization of LS tumours and of matched tumour-distant reference colonic mucosa based on whole-genome DNA-sequencing and RNA-sequencing analyses. Our data support two subgroups of LS-CRCs, G1 and G2, whereby G1 tumours show a higher number of somatic mutations, a higher amount of microsatellite slippage, and a different mutation spectrum. The gene expression phenotypes support this difference. Reference mucosa of G1 shows a strong immune response associated with the expression of HLA and immune checkpoint genes and the invasion of CD4+ T cells. Such an immune response is not observed in LS tumours, G2 reference and normal (non-Lynch) mucosa, and sporadic CRC. We hypothesize that G1 tumours are edited for escape from a highly immunogenic microenvironment via loss of HLA presentation and T-cell exhaustion. In contrast, G2 tumours seem to develop in a less immunogenic microenvironment where tumour-promoting inflammation parallels tumourigenesis. Larger studies on non-neoplastic mucosa tissue of mutation carriers are required to better understand the early phases of emerging tumours. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.