Abdulrahman Sibiany

Methylation of the Polycomb Group Target Genes Is a Possible Biomarker for Favorable Prognosis in Colorectal Cancer

Background: Colorectal cancer (CRC) is the second most common cancer in the Kingdom of Saudi Arabia with ever increasing incidence rates. DNA methylation is a common event in CRC where it is now considered an important phenomenon in CRC carcinogenesis and useful for the classification and prognosis of CRC. Methods: To gain insight into the molecular mechanisms underpinning CRC in Saudi Arabian patients, we profiled the DNA methylation frequency of key genes (MLH1, MSH2, RASSF1A, SLIT2, HIC1, MGMT, SFRP1, MYOD1, APC, CDKN2A, as well as five CIMP markers) in 120 sporadic CRC cases. CRC tumors originating from the rectum, left, and right colons are represented in this cohort of formalin-fixed paraffin-embedded tissues. Results: The most common methylation frequency was detected in the polycomb group target genes (PCGT) including SFRP1 (70%), MYOD1 (60.8%), HIC1 (61.7%), and SLIT2 (56.7%). In addition, MGMT methylation was detected at a high frequency (68.3%). RASSF1A, APC, and CDKN2A methylation frequencies were 42.5%, 25%, and 32.8%, respectively. K-means clustering analysis of the methylation events results in the clustering of the CRC samples into three groups depending on the level of methylation detected. Conclusion: Group II (PCGT methylation and CIMP-negative) methylation signature carried a favorable prognosis for male patients, whereas older patients with group I rare methylation signature have a potentially poorer clinical outcome. Impact: Methylation of the PCGT genes along with RASSF1A, APC, and MGMT can be potentially used as a new biomarker for the classification and prognosis of CRC tumors and independently of where the tumor has originated. Cancer Epidemiol Biomarkers Prev; 21(11); 2069–75. ©2012 AACR.

Cyclooxygenase-2 expression as a predictor of outcome in colorectal carcinoma.

AIM To correlate cyclooxygenase-2 (COX-2) expression profile with clinical and pathological variables to assess their prognostic/predictive value in colorectal carcinoma (CRC). METHODS Archival tumor samples were analyzed using immunohistochemistry for COX-2 expression in 94 patients with CRC. Patients were diagnosed and treated at the Departments of Surgery and Oncology, King Abdulaziz University Hospital, Saudi Arabia. RESULTS Fifty-six percent of the tumors showed positive cytoplasmic COX-2 expression, whereas 44% of cases were completely COX-2-negative. There were no significant correlations between COX-2 expression and sex, age, grade or tumor location. However, COX-2 expression revealed a significant correlation with tumor stage (P = 0.01) and distant metastasis (P = 0.02), and a borderline association with lymph node involvement (P = 0.07). Tumors with high COX-2 expression showed a higher recurrence rate than tumors with no expression (P < 0.009). In univariate Kaplan-Meier survival analysis, there was a significant (P = 0.026) difference in disease-free survival between COX-2-positive and negative tumors in favor of the latter. COX-2 expression did not significantly predict disease-specific survival, which was much shorter for COX-2-positive tumors. In multivariate (COX) models, COX-2 did not appear among the independent predictors of disease-free survival or disease-specific survival. CONCLUSION COX-2 expression seems to provide useful prognostic information in CRC, while predicting the patients at high risk for recurrent disease.

RECTAL CANCER ASSOCIATED WITH SCHISTOSOMIASIS: REPORT OF TWO CASES AND REVIEW OF THE LITERATURE

Rectal cancer is one of the most common malignancies in the West. The incidence in the developing countries is also increasing. There are various reasons for this escalation, including changes in dietary habits, particularly among urban dwellers, and parasitic infections. The risk of colorectal cancer is known to be increased in patients with long-standing schistosomal colitis. We present two male patients who had low rectal cancer (pT3N3M0, and pT3N2M0) for which they were treated with A-P resection and adjuvant chemoradiation. Histological examination of the specimen revealed moderately differentiated adenocarcinoma with extensive schistosomal colitis. The literature was reviewed. The relation between colorectal cancer and intestinal schistosomiasis should be considered as precancerous.

Recurrent intestinal perforations as a presentation of antiphospholipid syndrome.

Ann Saudi Med 2006;26(1):52-55 Antiphospholipid syndrome (APS) is a rare but important cause of thrombosis. It is suspected in patients who present with recurrent thrombosis or thrombosis in an unusual site. Gastrointestinal involvement is rare in this syndrome. Moreover, intestinal perforation in APS is very rare. We report a 19-year-old female patient who developed recurrent spontaneous intestinal perforations in which repeated laparotomies were undertaken and different diagnoses were entertained. The patient had received different treatments but without improvement. Antiphospholipid syndrome (APS) was suspected and diagnosed, and subsequently anticoagulant therapy was started. To our knowledge, this is a first report describing recurrent small intestinal perforation in a patient with APS.

Abnormal Anatomical Variations of Extra-Hepatic Biliary Tract, and Their Relation to Biliary Tract Injuries and Stones Formation

Background To determine the most common abnormal anatomical variations of extra-hepatic biliary tract (EHBT), and their relation to biliary tract injuries and stones formation. Methods This is a retrospective review of 120 patients, who underwent endoscopic retrograde cholangiopancreaticography (ERCP) and/or magnetic resonance cholangiopancreaticography (MRCP), between July 2011 and June 2013. The patients’ ERCP and MRCP images were reviewed and evaluated for the anatomy of EHBT; the medical records were reviewed for demographic data, biliary tracts injuries and stones formation. Results Out of 120 patients, 50 were males (41.7%) and 70 were females (58.3%). The mean age was 54 years old (range 20 - 88). Abnormal anatomy was reported in 30% (n = 36). Short cystic duct (CD) was found in 20% (n = 24), left CD insertion in 5% (n = 6), CD inserted into the right hepatic duct (RHD) in 1.7% (n = 2), duct of Luschka in 3.33% (n = 4) and accessory hepatic duct in also 3.33% (n = 4). Biliary tract injuries were reported in 15% (n = 18) and stones in 71.7% (n = 86). Biliary tract injuries were higher in abnormal anatomy (P = 0.04), but there was no relation between abnormal anatomy and stones formation. Conclusion Abnormal anatomy of EHBT was found to be 30%. The most common abnormality is short CD followed by left CD insertion. Surgeons should be aware of these common abnormalities in our patients, hence avoiding injuries to the biliary tract during surgery. The abnormal anatomy was associated with high incidence of biliary tract injury but has no relation to biliary stone formation.

Detection of human papillomavirus infection by molecular tests and its relation to colonic polyps and colorectal cancer

Objectives: To prospectively examine the association between human papilloma virus (HPV) colonization of the colonic mucosa and the development of colorectal polyps (CRPs), and colorectal cancer (CRC) in Saudi Arabia. Methods: A case control study was performed between January 2013 and December 2014. All eligible patients underwent standard diagnostic colonoscopy. Patients with polyps or colorectal cancer were considered cases, while those with any other endoscopic findings were controls. Biopsy samples from polyps and tumors, and/or from normal colonic mucosa were acquired. Human papilloma virus colonization was detected using a hybrid capture technique of samples taken from both normal tissue, and CRPs and CRC. The association between HPV and CRPs/CRC was evaluated. Results: A total of 132 patients were recruited. The mean age was 53 (±15.9) years. Sixty patients had endoscopically detectable CRPs/CRC, and 72 had either inflammation or normal endoscopic evaluations. Only 4 (0.8%) of the 132 samples that were collected and analyzed were positive for the HPV gene. Statistical analysis did not identify any significant association between HPV colonization and the presence of CRPs/CRC. The only significant predictor of detecting CRPs/CRC on colonoscopy was symptomatic presentation (odds ratio=11.072, 95% confidence interval 4.7-26.2, p<0.001). Conclusion: Human papilloma virus colonic colonization is rare in Saudi Arabia. An association between HPV colonization and CRP/CRC development could not be identified in this cohort of patients.

Membranous or Cytoplasmic HER2 Expression in Colorectal Carcinoma: Evaluation of Prognostic Value Using Both IHC & BDISH

ABSTRACT Background: Human epidermal growth factor recptor-2 (HER2) was identified as a driver gene in several types of cancers with both prognostic and predictive value. However, the molecular association of HER2 gene mutation with HER2 gene amplification and/or protein expression in cancer tissues has not been clearly defined. Moreover, there is little information available on HER2 status role in tumor progression and metastasis in colorectal carcinoma (CRC) compared to other solid tumors. The aim of this study was to evaluate both HER2 amplification and protein expression profiles using immunohistochemistry (IHC) and bright-field dual in situ hybridization (BDISH) techniques, respectively. Patients and methods: Tissue microarray (TMA) was constructed to accommodate a total of 243 CRC formalin-fixed paraffin embedded (FFPE) samples of consent patients and stained by IHC and BDISH methods. The expression patterns of HER2 protein status were evaluated and correlated to HER2 gene amplification status and then assessed for its prognostic value. Results: The expression profile of 58% samples showed cytoplasmic expression patterns of different categories. Interestingly, only 1% showed strong (+3) membranous expression pattern of HER2 with perfect match with their corresponding gene amplification status (>2). However, the cytoplasmic HER2 protein status did not show significant correlation with most clinicopathological features and survival outcomes except with age (p = 0.04) and tumor size (p = 0.03). Conclusion: We demonstrated that the membranous HER2 gene/protein status is infrequent, while the main fraction of HER2 overexpression was cytoplasmic and lacking prognostic value. This cytoplasmic HER2 overexpression was induced through a gene-amplification independent pathway, making the HER2 gene status evaluation approach in those cases not worthy. Further investigations about the molecular pathways of the cytoplasmic HER2 protein in CRC and its associations with survival outcomes are required to allow either a breakthrough in CRC management; or to confirm the hypothesis of a marginal role in CRC onset and progression.