Analysis of microsatellite instability in gastric mucosa-associated lymphoid tissue lymphoma

In Helicobacter pylori gastritis, constant antigenic stimulation triggers a sustained B-cell proliferation. Errors made during this continuous DNA replication are supposed to be corrected by the DNA mismatch repair mechanism. Failure of this mismatch repair mechanism has been described in hereditary non-polyposis colorectal cancer (HNPCC) and results in a replication error phenotype. Inherent to their instability during replication, microsatellites are the best markers of this replication error phenotype. We aimed to evaluate the role of defects in the DNA mismatch repair (MMR) mechanism and microsatellite instability (MSI) in relation to the most frequent genetic anomaly, translocation t(11;18)(q21;q21), in gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Therefore, we examined 10 microsatellite loci (BAT25, BAT26, D5S346, D17S250, D2S123, TGFB, BAT40, D18S58, D17S787 and D18S69) for instability in 28 patients with MALT lymphomas. In addition, these tumors were also immunostained for MLH1, MSH2, MSH6 and PMS2, as well as screened for the presence of t(11;18)(q21;q21) by real-time polymerase chain reaction (RT-PCR). We found MSI in 5/28 (18%) lymphomas, with MSI occurring in both t(11;18)(q21;q21)-positive and -negative tumors. One tumor displayed high levels of instability, and, remarkably, this was the only case displaying features of a diffuse large B-cell lymphoma. All microsatellite unstable lymphomas showed a loss of MSH6 expression. In conclusion, our data suggest that a MMR-defect may be involved in the development of gastric MALT lymphomas, and that a defect of MSH6 might be associated with those MSI-driven gastric lymphomas.status: publishe

Outcomes of elective and non-elective fenestrated-branched endovascular aortic repair for treatment of thoracoabdominal aortic aneurysms

Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.This work was presented at the 143rd Annual Meeting of the American Surgical Association, Toronto, Ontario, Canada, April 20-22, 2023.Objective: To describe outcomes after elective and non-elective fenestrated-branched endovascular aortic repair (FB-EVAR) for thoracoabdominal aortic aneurysms (TAAAs). Background: FB-EVAR has been increasingly utilized to treat TAAAs; however, outcomes after non-elective versus elective repair are not well described. Methods: Clinical data of consecutive patients undergoing FB-EVAR for TAAAs at 24 centers (2006-2021) were reviewed. Endpoints including early mortality and major adverse events (MAEs), all-cause mortality, and aortic-related mortality (ARM), were analyzed and compared in patients who had non-elective versus elective repair. Results: A total of 2603 patients (69% males; mean age 72±10 year old) underwent FB-EVAR for TAAAs. Elective repair was performed in 2187 patients (84%) and non-elective repair in 416 patients [16%; 268 (64%) symptomatic, 148 (36%) ruptured]. Non-elective FB-EVAR was associated with higher early mortality (17% vs 5%, P <0.001) and rates of MAEs (34% vs 20%, P <0.001). Median follow-up was 15 months (interquartile range, 7-37 months). Survival and cumulative incidence of ARM at 3 years were both lower for non-elective versus elective patients (50±4% vs 70±1% and 21±3% vs 7±1%, P <0.001). On multivariable analysis, non-elective repair was associated with increased risk of all-cause mortality (hazard ratio, 1.92; 95% CI] 1.50-2.44; P <0.001) and ARM (hazard ratio, 2.43; 95% CI, 1.63-3.62; P <0.001). Conclusions: Non-elective FB-EVAR of symptomatic or ruptured TAAAs is feasible, but carries higher incidence of early MAEs and increased all-cause mortality and ARM than elective repair. Long-term follow-up is warranted to justify the treatment.info:eu-repo/semantics/publishedVersio