Abdel Meguid Kassem

Promoter hypermethylation of RASSF1A, MGMT, and HIC-1 genes in benign and malignant colorectal tumors

Hypermethylation at the promoter region is an important epigenetic mechanism underlying the inactivation of tumor suppressor genes and frequently occurs as an early event in the development of different types of cancer including colorectal carcinoma (CRC). The aim of the present study is the detection of methylation status for some tumor suppressor genes including RASSF1A, MGMT, and HIC-1 in both cancerous and precancerous lesions of colorectal mucosa to evaluate the possibility of developing epigenetic biomarker for early detection of Egyptian CRC. Tissue biopsy was collected from 72 patients (36 CRC, 17 adenomatous polyps, and 19 ulcerative colitis), and in addition, adjacent normal-appearing tissues were collected as control. Promoter hypermethylation status for RSSAF1A, MGMT, and HIC-1 genes was detected after isolation of genomic DNA from the tissues samples using methylation-specific PCR technique. High frequency of methylation at MGMT, RASSFA, and HIC-1 was detected in CRC patients (25%, 47.2%, and 41.7% respectively). The highest methylation detected in adenomatous polyps patients was in MGMT gene (47.1%) followed by 35.3% for HIC-1 and only 5.9% for RASSF1A gene. HIC-1 gene exhibited highest frequency of methylation in ulcerative colitis patients (57.8%) whereas it was 26.3% for both RASSF1A and MGMT genes. A nonsignificant association was recorded between the methylation status in different genes examined with the clinicopathological factors except the association between methylation at RASSF1A gene with gender (p = 0.005), and it was significant. In conclusion, aberrant hypermethylation at promoter region of RASSFA, MGMT, and HIC-1 genes is involved in Egyptian CRCs. Hypermethylation of MGMT and HIC-1 genes plays an important role in the initiation of disease especially ulcerative colitis–carcinoma pathway.

Detection of ascitic fluid infections in patients with liver cirrhosis and ascites

BACKGROUND AND STUDY AIMS Ascitic fluid infections (AFIs) are the frequent complications of advanced liver disease. Bacterial translocation is considered a key step in the pathogenesis of gut-derived bacterial infections; mainly spontaneous bacterial peritonitis (SBP) in cirrhotic patients. Bacterial DNA (bactDNA) in ascitic fluid and serum has been suggested as a surrogate marker for bacterial translocation. We attempted at the isolation and identification of bacteria in ascitic fluid in cirrhotic patients and the assessment of polymerase chain reaction (PCR) in ascitic fluid and serum. PATIENTS AND METHODS Fifty cirrhotic patients having ascites with no signs of infection were included. Ascitic fluid cultures were obtained from patients. Ascitic fluid and serum were subjected to DNA extraction and PCR for the universal amplification of a region of the 16S ribosomal RNA (16S rRNA) gene to detect bactDNA. RESULTS Bacteria were isolated from 9 (18%) of the ascitic fluid samples, and were mainly Gram-positive bacteria. BactDNA was detected simultaneously in the ascitic fluid and serum of 17 (34%) patients and in the ascitic fluid of only 2 patients. In a single patient with positive ascitic fluid culture no bactDNA was detected in ascitic fluid or serum. By considering AFIs as a positive ascitic fluid culture and/or the presence of bactDNA in the ascitic fluid and/or serum, ascitic fluid culture could detect 9 out of 20 patients with AFIs (45%), PCR of ascitic fluid could detect 19 out of 20 (95%) while PCR of serum could detect 17 out of 20 (85%). In 10 patients with culture negative non-neutrocytic ascites (CNNNA) bactDNA could be detected in serum and ascitic fluid. CONCLUSION AFI can be caused by Gram positive as well as Gram negative organisms. A substantial percentage of cases with CNNNA show bactDNA in serum and ascitic fluid. PCR of ascitic fluid should, therefore, be used in the diagnostic workup of suspected cases of ascitic fluid infections.

The Future Role of the Gastroenterologist in Digestive Oncology: An International Perspective

*Memorial Sloan-Kettering Cancer Center, New York, New York; Stanford University School of Medicine, Palo Alto, California; Ruhr-University Bochum, Bochum, ermany; The Mayo Clinic, Rochester, Minnesota; The Chinese University of Hong Kong, The People’s Republic of China; Martin-Luther-University, Halle‡‡ §§ ittenberg, Halle (Saale), Germany; **Cairo University, Cairo, Egypt; Tehran University of Medical Science, Tehran, Iran; Technische Universitaet Muenchen, Munich, Germany; and Academic Medical Center, Amsterdam, The Netherlands

Mutational Hotspots in the Mitochondrial D-Loop Region of Cancerous and Precancerous Colorectal Lesions in Egyptian Patients

Mutations in the mitochondrial genome (mtDNA) are associated with different types of cancer, specifically colorectal cancer (CRC). However, few studies have been performed on precancerous lesions, such as ulcerative colitis (UC) lesions and adenomatous polyps (AP). The aim of this study was to identify mtDNA mutations in the cancerous and precancerous lesions of Egyptian patients. An analysis of the mutations found in six regions of the mtDNA genome (ND1, ND5, COI, tRNAser, D-loop 1, and 2) in 80 Egyptian patients (40 CRC, 20 UC, and 20 AP) was performed using polymerase chain reaction-single-strand conformational polymorphism techniques and followed up by direct sequencing. The overall incidence of mutations was 25%, 25%, and 35% in CRC, UC, and AP cases, respectively. Although there was no common mutation pattern within each group, a large number of mutations were detected in the D-loop region in all of the groups. Some mutations (e.g., T414G) were detected repeatedly in precancerous (UC and AP) and cancerous lesions. Mutations detected in patients with CRC were predominantly found in the ND1 gene (40%). Our preliminary study suggests that Egyptian patients with CRC have a large number of mtDNA mutations, especially in the D-loop region, which have not been previously reported. Mutations in the mtDNA of precancerous lesions (i.e., AP and UC) may contribute to transformation events that lead to CRC.

APRI test and hyaluronic acid as non-invasive diagnostic tools for post HCV liver fibrosis: Systematic review and meta-analysis

BACKGROUND AND STUDY AIMS Hepatitis C virus (HCV) accounts for a sizable proportion of chronic liver disease cases and represents the most common indication for liver transplantation. Precise diagnosis of hepatic fibrosis stage is considered a funnel-neck in proper management and follow-up of HCV-infected patients. Given the possible complications of liver biopsy, a non-invasive method for assessing hepatic fibrosis is needed. This study aimed to evaluate the diagnostic accuracy of APRI and hyaluronic acid as non-invasive diagnostic assessment tools for post HCV liver fibrosis. PATIENTS AND METHODS Systematic literature searching identified studies performed on Egyptian territory to evaluate APRI and hyaluronic acid as non-invasive tests of fibrosis and using liver biopsy as the reference standard. Meta-analysis was performed for areas with an adequate number of publications. Validation of meta- analysis on APRI was done on a subset of 150 treatment-naïve post-hepatitis C patients. RESULTS Both APRI and hyaluronic acid have superior predictive power for hepatic cirrhosis (F4) than for significant fibrosis (F2-F3). The pooled estimate for sensitivities and specificities of APRI and hyaluronic acid to diagnose F4 were (84% and 82%) and (83% and 89%) respectively. In the subgroup of treatment naïve post-hepatitis C patients, APRI had higher diagnostic performance to diagnose liver cirrhosis with 93.8% sensitivity and 72.4% specificity (AUC; 0.908, 95%CI; 0.851-0.965, p-value; <0.001) compared to its accuracy to diagnose significant hepatic fibrosis with 65.1% sensitivity and 77.8% (AUC; 0.685, 95% CI; 0.59-0.78, p-value; 0.001). CONCLUSION APRI score and hyaluronic acid levels are simple and reliable non-invasive markers to detect advanced fibrosis among post-hepatitis C patients.

Endosonographic imaging in pancreatic disease

Since its introduction in the early 1980s, endoscopic ultrasound (EUS) has revolutionized the imaging of the pancreas. The technique has proved reliable in the detection and assessment of small pancreatic lesions and accurate in the preoperative staging of pancreatic carcinoma when compared with other techniques such as abdominal ultrasound, endoscopic retrograde cholangiopancreatography, computed tomography, and nuclear magnetic resonance imaging. Other indications in which EUS has shown to be valuable include acute and chronic pancreatitis, tumors of the papilla of Vater, choledocholithiasis, as well as common bile duct tumors. Interventional EUS, including fine-needle aspiration puncture of pancreatic tumors and celiac plexus neurolysis for the palliation of pain in chronic pancreatitis or pancreatic carcinoma, is increasingly being performed. In this article, EUS imaging in pancreatic diseases is described, pointing out its uses and accuracy in various lesions.