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AIM: To compare molecular profiles of proximal colon, distal colon and rectum in large adenomas, early and late carcinomas. To assess feasibility of testing directed at molecular markers from this study in routine clinical practice. METHODS: A prospective 3-year study has resulted in the acquisition of samples from 159 large adenomas and 138 carcinomas along with associated clinical parameters including localization, grade and histological type for adenomas and localization and stage for carcinomas. A complex molecular phenotyping has been performed using multiplex ligation-dependent probe amplification technique for the evaluation of CpG-island methylator phenotype (CIMP), PCR fragment analysis for detection of microsatellite instability and denaturing capillary electrophoresis for sensitive detection of somatic mutations in KRAS, BRAF, TP53 and APC genes. RESULTS: Molecular types according to previously introduced Jass classification have been evaluated for large adenomas and early and late carcinomas. An increase in CIMP+ type, eventually accompanied with KRAS mutations, was notable between large adenomas and early carcinomas. As expected, the longitudinal observations revealed a correlation of the CIMP+/BRAF+ type with proximal location. CONCLUSION: Prospective molecular classification of tissue specimens is feasible in routine endoscopy practice. Increased frequency of some molecular types corresponds to the developmental stages of colorectal tumors. As expected, a clear distinction is notable for tumors located in proximal colon supposedly arising from the serrated (methylation) pathway.

Background Colorectal cancer (CRC) is the 3rd most common cancer worldwide and the Czech Republic has the 6th highest incidence of CRC worldwide. Large intestinal microbiota play in its etiopathogenesis important role. Bacteriocins are proteins, produced by bacteria from the Enterobacteriaceae family. The aim of our prospective study was to assess the colonization of large intestinal mucosa by Escherichia coli strains and to investigate their bacteriocin production. Methods A total of 30 consecutive patients with colorectal adenoma, CRA (17 men, 13 women, aged 39–79, mean age 63 ± 9), 30 patients with CRC (23 men, 7 women, aged 38–86, mean age 67 ± 11) and 20 healthy controls (9 men, 11 women, age 23–84, mean age 55 ± 15) were enrolled into prospective study. Mucosal biopsies were taken in the caecum, transverse colon and rectum during pancolonoscopy. Microbiological culture, isolation and identification of bacteria followed. Bacteriocin production was assessed by growth inhibition of indicator strains E. coli K12-Row, E. coli C6 (phi), and Shigella sonnei 17. Identification of bacteriocin-encoding determinants and E. coli phylogroups was performed using PCR methods. Results A total of 622 strains were isolated and further investigated. A significantly higher frequency of simultaneous production of colicins and microcins was revealed in the group of patients with CRC, when compared to patients with CRA, p = 0.031. A significantly higher frequency of E. coli phylogroup D was found in patients with CRC, when compared to controls, p = 0.044. A significantly higher prevalence of bacteriocinogeny was confirmed in patients with advanced adenoma when compared to patients with non-advanced adenoma, p = 0.010. Increasing bacteriocinogeny was associated with an increasing stage of CRC (assessed according to TNM classification). Either E. coli phylogroup B2 or E. coli phylogroup D were isolated in biopsies of patients with right-sided CRC. A statistically higher incidence of E. coli phylogroup B2 was found in patients with right-sided CRC when compared to patients with left-sided CRC, p = 0.028. Conclusions Large intestinal mucosa of patients with more advanced colorectal neoplasia is colonized with more virulent strains of E. coli and higher production of bacteriocins is observed in these patients when compared to those with less advanced colorectal neoplasia. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0733-7) contains supplementary material, which is available to authorized users.

OBJECTIVE. Inflammatory bowel disease (IBD) can be associated with hypercoagulable disorders. Aim of this single-center, prospective study was an in-depth evaluation of acquired hypercoagulable states in IBD patients. METHODS. A total of 110 patients with Crohn's disease (CD) (aged 19-69; mean 40.5, median 38.5 years), 43 with ulcerative colitis (UC) (aged 17-72; mean 42, median 36 years), and 30 controls were enrolled. Full blood count, serum C-reactive protein (CRP), proteins C and S, activated protein C (APC) resistance, thrombin-antithrombin complex (TAT), F1+F2 fragments, tissue factor pathway inhibitor (TFPI) total and truncated, TFPI-factor Xa, tissue plasminogen activator (tPA) and PAI-I antigen were investigated in peripheral blood samples. RESULTS. Only 18 of 153 (11.8%) IBD patients had hemocoagulation parameters within normal range. Significant difference between IBD patients and controls was found in thrombocyte volume (p < 0.001), protein C (p = 0.025), protein S (p = 0.003), APC resistance (p < 0.001), F1+F2 fragments (p < 0.001), and tPA (p = 0.002). In CD patients who were divided into two subgroups according to serum CRP values (non-active disease

642 Background: Patients with advanced stages of colorectal cancer have elevated levels of circulating-tumor DNA (ctDNA) in peripheral blood. Its presence can facilitate acquisition of DNA material for tumor molecular profiling without the invasive procedures. In this work we present utility of ctDNA for the determination of tumor phenotype within the basic division into the mutator phenotype (microsatellite instability, MSI and chromosomal instability, CIN) or methylator phenotype (CpG island methylator phenotype, CIMP). Methods: Tumor biopsy tissue and 5mL of peripheral blood samples were prospectively collected from 148 patients with colorectal tumors. In addition, plasma was extracted from peripheral blood immediately upon collection. Samples were then transported to the molecular laboratory where DNA and ctDNA were isolated from tissue and plasma, by a modified spin-column ctDNA extraction. Somatic mutations in tumor suppressors denoting CIN phenotype were detected by denaturing capillary electrophoresis (DCE), microsatellite instability was detected by MSI Analysis System, Version 1.2 (Promega corporation, Madison, WI) and DNA methylation (CIMP phenotype) was obtained by multiplex ligation-dependent probe amplification (MRC Holland, NL). Results: The samples included 75 adenomas and 70 carcinomas. The detected rates in tissues were: 4% for MSI, 32% for CIN and 7% for CIMP in adenomas and 10% for MSI, 36% for CIN and 32% for CIMP in carcinomas. In adenomas, none of the detected molecular types could be confirmed in ctDNA. In carcinomas, the concordance between tissue and ctDNA was 25% for MSI, 23% for CIN and 60% for CIMP. The success rates were related to the ctDNA concentration yields with a minimum requirement of ~0.2ng/uL. Conclusions: ctDNA may serve as alternative source for molecular classification of colorectal tumors (MSI, CIN and CIMP). A low concordance between tissue and ctDNA was found for CIN and MSI in comparison to 60% of CIMP-phenotypes found in both tissue as well as ctDNA. The results are predominantly dictated by disease stage and the corresponding levels of ctDNA. Supported by a Czech Ministry of health grant no. 14383.

Human intestinal microbiota create a complex polymicrobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO). SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract. There are several endogenous defence mechanisms for preventing bacterial overgrowth: gastric acid secretion, intestinal motility, intact ileo-caecal valve, immunoglobulins within intestinal secretion and bacteriostatic properties of pancreatic and biliary secretion. Aetiology of SIBO is usually complex, associated with disorders of protective antibacterial mechanisms (e.g. achlorhydria, pancreatic exocrine insufficiency, immunodeficiency syndromes), anatomical abnormalities (e.g. small intestinal obstruction, diverticula, fistulae, surgical blind loop, previous ileo-caecal resections) and/or motility disorders (e.g. scleroderma, autonomic neuropathy in diabetes mellitus, post-radiation enteropathy, small intestinal pseudo-obstruction). In some patients more than one factor may be involved. Symptoms related to SIBO are bloating, diarrhoea, malabsorption, weight loss and malnutrition. The gold standard for diagnosing SIBO is still microbial investigation of jejunal aspirates. Non-invasive hydrogen and methane breath tests are most commonly used for the diagnosis of SIBO using glucose or lactulose. Therapy for SIBO must be complex, addressing all causes, symptoms and complications, and fully individualised. It should include treatment of the underlying disease, nutritional support and cyclical gastro-intestinal selective antibiotics. Prognosis is usually serious, determined mostly by the underlying disease that led to SIBO.