Discovery of a novel and a rare Kristen rat sarcoma viral oncogene homolog (KRAS) gene mutation in colorectal cancer patients.

Colorectal cancer (CRC) is one of the most important causes of morbidity and mortality in the developed world and is gradually more frequent in the developing world including Saudi Arabia. According to the Saudi Cancer Registry report 2015, CRC is the most common cancer in men (14.9%) and the second most prevalent cancer. Oncogenic mutations in the KRAS gene play a central role in tumorigenesis and are mutated in 30-40% of all CRC patients. To explore the prevalence of KRAS gene mutations in the Saudi population, we collected 80 CRC tumor tissues and sequenced the KRAS gene using automated sequencing technologies. The chromatograms presented mutations in 26 patients (32.5%) in four different codons, that is, 12, 13, 17, and 31. Most of the mutations were identified in codon 12 in 16 patients (61.5% of all mutations). We identified a novel mutation c.51 G>A in codon 17, where serine was substituted by arginine (S17R) in four patients. We also identified a very rare mutation, c.91 G>A, in which glutamic acid was replaced by lysine (E31K) in three patients. In conclusion, our findings further the knowledge about KRAS mutations in different ethnic groups is indispensable to fully understand their role in the development and progression of CRC.

Array comparative genomic hybridization based identification of key genetic alterations at 2p21-p16.3 (MSH2, MSH6, EPCAM), 3p23-p14.2 (MLH1), 7p22.1 (PMS2) and 1p34.1-p33 (MUTYH) regions in hereditary non polyposis colorectal cancer (Lynch syndrome) in the Kingdom of Saudi Arabia.

Lynch syndrome is inherited in an autosomal dominant mode. Lynch syndrome is caused by impairment of one or more of the various genes (most frequently MLH1 and MSH2) involved in mismatch repair. In this study, whole genome comparative genomic hybridization array (array CGH) based genomic analysis was performed on twelve Saudi Lynch syndrome patients. A total of 124 chromosomal alterations (structural loss) were identified at mean log2 ratio cut off value of ±0.25. We also found structural loss in 2p21-p16.3, 3p23-p14.2, 7p22.1 and 1p34.1-p33 regions. These findings were subsequently validated by real time quantitative PCR showing downregulation of MSH2, MSH6, EPCAM, MLH1, PMS2 and MUTYH genes. These findings shall help in establishing database for alterations in mismatch repair genes underlying Lynch syndrome in Saudi population as well as to determine the incidence ratio of these disorders. Guided counselling will subsequently lead to the prevention and eradication of Lynch Syndrome in the local population.

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

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.

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 less than 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.

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.

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.

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.

Mediastinal parathyroid adenoma.

We present two cases that developed clinical, biochemical and radiological evidences of primary and secondary hyperparathyroidism. In the first case the adenoma was removed through a transcervical incision and in the second case the supernumerary adenoma was removed through sternotomy. Post operatively, patients had normal serum calcium and iPTH with complete disappearance of symptoms.

Comparison of students' performance in the traditional oral clinical examination and the objective structured clinical examination.

OBJECTIVE: To find out whether the objective structured clinical examination (OSCE) using standardized patients allows the same evaluation of students as the traditional oral clinical examination (TOCE) using real patients. METHODS: The results of 4 cohorts of students (904 students) in the end of posting examination (using the TOCE), and the end of year examination (using OSCE) during the academic years 2003-2006 at King Abdulaziz University, Faculty of Medicine, Jeddah, Kingdom of saudi Arabia were analyzed retrospectively. Spearman's correlation coefficient was calculated for comparison of performance in the different parts of the 2 examinations. RESULTS: There was a strong positive correlation between the results of the OSCE and the final grade of the students (r=0.786), and between the TOCE and the final grade of the students (r=0.591). The coefficient for correlation between the results of the OSCE and TOCE was 0.406. CONCLUSION: The OSCE can be used for the evaluation of clinical skills like the TOCE with better objectivity and reliability.

Structural study on cultured isolated fetal rat pancreatic islets.

OBJECTIVE: To perform a morphometric and structural study of the cultured isolated fetal rat pancreatic islets. METHODS: Islets of the fetal rat pancreas, aged 22 days were isolated by the standard procedure of collagenase digestion and culture technique. The islets were cultured for 1, 2, 3, 4 and 5 days. The islets were counted under a dissecting microscope and islet diameter and purity were measured under a phase contrast microscope fitted with a calibrated grid. The islet specimens were fixed in buffered neutral formalin, dehydrated in alcohol and embedded in parablast. Sections were stained with hematoxylin and eosin. This study was conducted in King Fahd Medical Research Center, Faculty of Medicine, King Abdul-Aziz University, Kingdom of Saudi Arabia, during 2003 and 2004. RESULTS: The purity of the cultured islets gradually increased with time and was significantly different between the cultured groups. The number of the cultured islets gradually decreased with time. The islet diameter gradually increased with culture period. The islet purity and diameter were significantly different between the cultured groups. Parablast sections stained with hematoxylin and eosin showed that the shape and histological structure of the cultured islets were intact. CONCLUSION: The results of the present work represent an extensive morphometric structural study of isolated cultured fetal islets. The culture islet diameter and purity showed gradual increase with culture period, while the islet number showed gradual decrease.

Wandering spleen.

Congenital malformations of the spleen are rare. We report 3 cases of wandering spleen presented as abdominal or pelvi-abdominal mass. Two patients were suffering from chronic lower abdominal pain with thrombosed splenic pedicle and the third patient had an acute abdomen. All patients underwent splenectomies. Abdominal ultrasound, computerized tomography, Doppler ultrasound, and radioisotope studies were used to confirm the diagnosis. The clinical, diagnostic and treatment modalities are discussed.

Spontaneous rupture of hepatocellular carcinoma.

Hepatocellular carcinoma is the most common malignancy among males and the 7th among female patients in the Kingdom of Saudi Arabia. This is due to the endemicity of hepatitis B and hepatitis C. Spontaneous rupture of hepatocellular carcinoma is rare. We report 4 cases of spontaneous rupture of hepatocellular carcinoma. Initial control of bleeding was achieved surgically in 3 patients and by embolization in the 4th patient. All patients had very good hepatic reserve as reflected by Child-Pugh scoring (A & B). We found that the incidence of ruptured hepatocellular carcinoma among 85 patients was 4.7%. The prognosis of this subgroup of patients is poor as reflected by the low median survival ranging from 6-16 weeks.

Delayed presentation of traumatic diaphragmatic rupture.

We present a case of traumatic diaphragmatic rupture that presented two years after the initial thoracic injury. The patient presented with intestinal obstruction and colonic perforations. Through laparotomy, the diaphragmatic defect was repaired and the colonic perforations were closed. The patient had an uneventful post-operative recovery.