Search

Background: Colorectal cancer (CRC) is the leading gastrointestinal malignancy. The development from premalignant intraepithelial lesions leading to invasive cancer is paradigmatic for the stepwise carcinogenesis of epithelial cancers, but the knowledge of the underlying mechanism of carcinogenesis and progression of CRC is still incomplete. The understanding of epigenetic mechanisms of carcinogenesis has led to new therapeutic approaches during the last years. Enhancer of zeste homolog 2 (EZH2) is one central epigenetic silencer of the polycomb repressor complex 2 (PRC2) that is already in clinical use as a novel drug target and is associated with poorer prognosis in several cancer entities. Patients and Methods: The protein expression of EZH2 and other members of the PRC2 as well as resulting posttranslational modifications were investigated by immunohistochemistry in 187 patients with CRC and in 94 patients with premalignant colorectal lesions and correlated with their clinical outcome. Furthermore, the corresponding mRNA expression levels were analyzed in 217 patients with rectal cancer that were enrolled in a prospective clinical trial. Results: We found a weak expression of EZH2 in normal colon mucosa that increased in low grade, peaked in high grade intraepithelial neoplasia, and decreased again in invasive CRC. The posttranslational modification caused by EZH2 as a measure of EZH2 activity showed the same behavior. Strong protein and mRNA expression of EZH2 were significantly correlated with favorable prognosis in both investigated cohorts. Conclusion: The expression and activity of EZH2 are associated with colorectal carcinogenesis and most expressed in intraepithelial high-grade lesions. Strong expression of EZH2 is associated with a significantly favorable prognosis in patients suffering from CRC. [ABSTRACT FROM AUTHOR]

Background and Aims: Testing for Helicobacter pylori is frequently conducted during esophagogastroduodenoscopy (EGD). Suppressive conditions such as the intake of proton-pump inhibitors (PPIs), preceded antibiotic treatment or recent upper gastrointestinal bleeding impair H. pylori test quality. The aim of our study was to evaluate the frequency and pattern of H. pylori suppressive conditions in a large patient collective undergoing elective EGD in a German university hospital. Methods: The trial was performed as a single-center study. Only elective EGD from inpatients and outpatients were included. Prior to endoscopy, H. pylori suppressive conditions were collected using a standardized questionnaire. If H. pylori testing was indicated according to the guidelines, always both histology and helicobacter urease test were performed in analogy to the Sydney classification. Results: One thousand six hundred and thirty-one patients were included (median 61 years, 36.0% outpatients, 64.0% inpatients). Overall, 76.5% of patients were under H. pylori suppressive conditions. The main suppressive condition was the intake of PPIs (70.7%). In 819 (50.2%) of all included cases, H. pylori testing was performed. The following were the results: 17.3% (142) had a positive H. pylori testing and 82.7% (677) were negative. Of those with negative result, 70.0% were tested under suppressive conditions. Conclusion: Guidelines recommend H. pylori testing under non-suppressive conditions. However, this does not always meet the clinical practice. Our data show that de facto, many patients undergoing elective EGD are tested for H. pylori under suppressive conditions coming along with a higher risk of potentially false negative results. Particularly, concerning this issue, further research is needed to improve and clarify everyday clinical practice. [ABSTRACT FROM AUTHOR]