Ischemic Conditioning in the Right Colon and Terminal Ileum: An Experimental Rat Model.

INTRODUCTION: Preoperative gastric ischemic conditioning (IC) improves the outcome of esophageal replacement gastroplasty and is associated with low morbidity. However, when the stomach cannot be used for esophageal replacement, a colonic replacement is required. The study aim was to assess the viability of right colon and terminal ileum IC in a rat model and the histological damage/recovery sequence and determine if neovascularization is a potential adaptive mechanism. METHODS: The study was conducted in Rattus norvegicus with ileocolic vascular ligation. Seven groups of animals were established (6 rats per group) with groups defined by the date of their post-IC euthanasia (+1, +3, +6, +10, +15, and +21 days). Comparisons were made with a sham group. Viability of the model was defined as <10% of transmural necrosis. The evaluation of histological damage used the Chiu score in hematoxylin and eosin sections of paraffin-embedded specimens with CD31 immunohistochemical assessment of neovascularization by the median of submucosal vessel counts in 5 high-magnification fields. RESULTS: Transmural colon necrosis occurred in 1/36 animals (2.78%) with no animal demonstrating transmural ileal necrosis. The maximum damage was observed in the colon on +1 day post-IC (average Chiu score 1.67, p = 0.015), whereas in the ileum, it was on days +1, +3, and +6 (average Chiu score 1.5, 1.3, and 1.17; p = 0.015, 0.002, and 0.015, respectively). In the +21-day group, histological recovery was complete in the colon in 4 (66.7%) of the 6 animals and in the ileum in 5 (83.3%) of 6 animals. There were no significant differences in quantitative neovascularization in any of the groups when compared with the sham group or when comparisons were made between groups. CONCLUSIONS: The tested animal model for IC of the colon and terminal ileum appeared to be feasible. Histological damage was maximal between the 1st and 3rd day following IC, but by day 21, recovery was complete in two-thirds of the rats. There was no evidence in this preliminary IC model that would suggest neovascularization as an adaptive mechanism.

Comprehensive analysis of copy number aberrations in microsatellite stable colon cancer in view of stromal component.

BACKGROUND: Somatic copy number aberrations (CNAs) are common acquired changes in cancer cells having an important role in the progression of colon cancer (colorectal cancer, CRC). This study aimed to perform a characterisation of CNA and their impact in gene expression. METHODS: Copy number aberrations were inferred from SNP array data in a series of 99 CRC. Copy number aberration events were calculated and used to assess the association between copy number dosage, clinical and molecular characteristics of the tumours, and gene expression changes. All analyses were adjusted for the quantity of stroma in each sample, which was inferred from gene expression data. RESULTS: High heterogeneity among samples was observed; the proportion of altered genome ranged between 0.04 and 26.6%. Recurrent CNA regions with gains were frequent in chromosomes 7p, 8q, 13q, and 20, whereas 8p, 17p, and 18 cumulated losses. A significant positive correlation was observed between the number of somatic mutations and total CNA (Spearman's r=0.42, P=0.006). Approximately 37% of genes located in CNA regions changed their level of expression and the average partial correlation (adjusted for stromal content) with copy number was 0.54 (interquartile range 0.20 to 0.81). Altered genes showed enrichment in pathways relevant for CRC. Tumours classified as CMS2 and CMS4 by the consensus molecular subtyping showed higher frequency of CNA. Losses of one small region in 1p36.33, with gene CDK11B, were associated with poor prognosis. More than 66% of the recurrent CNA were validated in the The Cancer Genome Atlas (TCGA) data when analysed with the same procedure. Furthermore, 79% of the genes with altered expression in our data were validated in the TCGA. CONCLUSIONS: Although CNA are frequent events in microsatellite stable CRC, few focal recurrent regions were found. These aberrations have strong effects on gene expression and contribute to deregulate relevant cancer pathways. Owing to the diploid nature of stromal cells, it is important to consider the purity of tumour samples to accurately calculate CNA events in CRC.

Aberrant gene expression in mucosa adjacent to tumor reveals a molecular crosstalk in colon cancer.

BACKGROUND: A colorectal tumor is not an isolated entity growing in a restricted location of the body. The patient's gut environment constitutes the framework where the tumor evolves and this relationship promotes and includes a complex and tight correlation of the tumor with inflammation, blood vessels formation, nutrition, and gut microbiome composition. The tumor influence in the environment could both promote an anti-tumor or a pro-tumor response. METHODS: A set of 98 paired adjacent mucosa and tumor tissues from colorectal cancer (CRC) patients and 50 colon mucosa from healthy donors (246 samples in total) were included in this work. RNA extracted from each sample was hybridized in Affymetrix chips Human Genome U219. Functional relationships between genes were inferred by means of systems biology using both transcriptional regulation networks (ARACNe algorithm) and protein-protein interaction networks (BIANA software). RESULTS: Here we report a transcriptomic analysis revealing a number of genes activated in adjacent mucosa from CRC patients, not activated in mucosa from healthy donors. A functional analysis of these genes suggested that this active reaction of the adjacent mucosa was related to the presence of the tumor. Transcriptional and protein-interaction networks were used to further elucidate this response of normal gut in front of the tumor, revealing a crosstalk between proteins secreted by the tumor and receptors activated in the adjacent colon tissue; and vice versa. Remarkably, Slit family of proteins activated ROBO receptors in tumor whereas tumor-secreted proteins transduced a cellular signal finally activating AP-1 in adjacent tissue. CONCLUSIONS: The systems-level approach provides new insights into the micro-ecology of colorectal tumorogenesis. Disrupting this intricate molecular network of cell-cell communication and pro-inflammatory microenvironment could be a therapeutic target in CRC patients.

Nanofluidic digital PCR for KRAS mutation detection and quantification in gastrointestinal cancer.

BACKGROUND: Concomitant quantification of multiple mutant KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) alleles may provide information in addition to that provided by standard mutation-detection procedures. We assessed the feasibility of a nanofluidic digital PCR array platform to detect and quantify KRAS mutations simultaneously in clinically relevant samples. METHODS: We assessed 2 groups of patients (colorectal and pancreatic disease): Group 1 consisted of 27 patients with colorectal carcinomas, 14 patients with adenomas, and 5 control individuals; group 2 consisted of 42 patients with pancreatic carcinoma, 4 with adenocarcinomas of the ampulla, and 6 with chronic pancreatitis). Digital PCR was performed with the Digital Array Chip (Fluidigm). RESULTS: Nanofluidic digital PCR detected mutant alleles at 0.05% to 0.1%, depending on the variant analyzed. For the colorectal disease group, conventional PCR detected 9 (64%) of 14 adenomas that were positive for KRAS mutants, whereas digital PCR increased this number to 11 (79%) of 14. Sixteen (59%) of 27 carcinomas showed KRAS mutation with conventional PCR. Two additional cases were detected with digital PCR. In 5 cases (3 adenomas, 2 carcinomas), the total number of mutant alleles changed. For the pancreatic disease group, digital PCR increased the number of positive cases from 26 to 34 (81%) and identified ≥ 2 mutant alleles in 25 cases, compared with conventional PCR, which identified multiple KRAS mutant alleles in only 12 cases. A good correlation was observed between results obtained with tumor biopsies and those obtained with pancreatic juice. CONCLUSIONS: Digital PCR provides a robust, quantitative measure of the proportion of KRAS mutant alleles in routinely obtained samples. It also allows a better classification of tumors, with potential clinical relevance.

New Methylation Biomarker Panel for Early Diagnosis of Dysplasia or Cancer in High-Risk Inflammatory Bowel Disease Patients.

Background: The risk of developing colorectal cancer (CRC) is increased in patients with inflammatory bowel disease (IBD) of the colon. The aim of the study was to evaluate the effectiveness of selected methylation gene panel for the early detection of CRC in high-risk IBD patients. Methods: In a discovery phase, 73 biopsies of 48 IBD patients (associated or not to CRC) were analyzed from genome-wide DNA methylation analysis using the Illumina Human Methylation 450K BeadChip. The panel of 5 genes selected (EYA4, SLIT2, FLI1, USP44, and SND1) was validated prospectively using methylation-specific melting curve analysis in biopsies of diseased and adjacent healthy tissue of 203 patients: 38 with IBD and associated neoplasia, 81 patients with IBD (25 of them with high risk), 48 with sporadic CRC, and 36 healthy controls. Results: The prevalence of methylation was higher in patients with IBD and associated neoplasia (both in diseased and adjacent healthy tissue, 71% and 52%, respectively) than in healthy controls (2/36, 6%; P = 6.72E-05). Methylation in IBD patients at high risk of dysplasia or cancer was more frequently detected than in patients at low risk (92% vs 57%; odds ratio, 8.63; P = 0.001). EYA4 and SLIT2 were the markers most frequently methylated. Differences in methylation levels were more evident in healthy mucosa (82% vs 15% high vs low risk, respectively; P = 1.25E-05). Conclusions: Analysis of this panel of methylation markers may help in the early identification of colorectal dysplasia or cancer in high-risk IBD patients.

Interleukin-4 and interleukin-4 receptor polymorphisms and colorectal cancer risk.

Interleukin-4 (IL-4) and interleukin-4 receptor (IL-4R) modulate inflammation and are associated with the colorectal adenoma-carcinoma progression and the metastatic capacity. IL-4 also causes a dose-dependent reduction of proliferation in colorectal cancer cells. The aim of the study was to evaluate whether genetic variants within IL4 and IL4R could affect the individual risk to develop colorectal cancer. We genotyped all the polymorphisms coding for an aminoacidic change in IL4R and we used a haplotype-tagging SNP approach for IL4. We carried out a case-control association study by genotyping, with the 5' nuclease assay, two common SNPs within IL4 (-588C>T, Ex1-168G>A) and five SNPs within IL4R (I75V, C431R, S436L, S503P, Q576R) in 377 cases of colorectal cancer and 326 controls from Spain. No statistically significant association between the SNPs investigated and colorectal cancer risk was found, as main effects. When the sub-analyses were carried out, the homozygotes for IL4 -588C>T or for Ex1-168G>A showed an increased risk for colon cancer only, with the odds ratios of 4 (95% CI 0.97-16.6; P-interaction=0.016 and 4.66 (95% CI 1.16-18.77; P-interaction=0.023), respectively. Moreover, women showed a significant increased risk associated to the IL4 rare alleles and this was clearly greater than that in men (for Ex1-168G>A: OR=1.96; 95% CI=1.11-3.47; P-interaction=0.006). However, when sub-groups are analysed, the findings should be taken with caution for the weakening of the statistical power.

Association of common polymorphisms in inflammatory genes interleukin (IL)6, IL8, tumor necrosis factor alpha, NFKB1, and peroxisome proliferator-activated receptor gamma with colorectal cancer.

Animal models and epidemiological observations suggest that a continuous inflammatory condition predisposes to colorectal cancer (CRC), but the roles of different elements participating in inflammatory responses have been little investigated in relation to CRC. We have studied the association between single nucleotide polymorphisms in the interleukin (IL)-6 (-174 G>C), IL8 (-251T>A), tumor necrosis factor alpha (-308G>A), and PPARG (Pro12Ala) genes and the risk of CRC in a group of 377 cases and 326 controls from Barcelona, Spain. These genes are known to be important for inflammation of the colorectum and common allelic variants have been shown to have a biological effect. The PPARG Ala12 and IL8-251A genotypes are associated with reduced risk of disease (0.56, 95% CI, 0.37-0.85, P = 0.0056, and 0.70, 95% CI, 0.50-0.99, P = 0.043, respectively), whereas the IL6-174C genotype is associated with increased risk (1.53, 95% CI, 1.12-2.09, P = 0.0073). We also studied a single nucleotide polymorphism in intron 11 of the NFKB1 gene (rs1020759), which probably lacks any functional role, and found no significant association with the disease. This is the first report that IL6, IL8, and PPARG genes are important in relation to inflammation-related risk of sporadic CRC.

Apoptosis inhibition plays a greater role than necrosis inhibition in decreasing bacterial translocation in experimental intestinal transplantation.

BACKGROUND: During small-bowel transplantation, necrosis and apoptosis are involved in the destruction of intestinal epithelial cells. This study was conducted to assess which mode of cell death plays a greater role as a trigger of the bacterial translocation (BT) associated with intestinal transplantation. METHODS: The following experimental groups were studied: sham, Tx (intestinal transplantation), Tx + poly (ADP-ribose) synthetase (PARS) inhibitor 3-aminobenzamide (3-AB), and Tx + caspase inhibitor Z-VAD-fmk. Histological analysis, caspase-3 activity, DNA fragmentation, and BT were measured in tissue samples after transplantation. RESULTS: During intestinal transplantation, apoptosis and necrosis both increased, showing graft injury and high levels of BT. Rats treated with 3-AB showed histological protection of the transplanted graft and a tendency toward lower BT despite the existence of high apoptosis levels. The rats treated with Z-VAD showed histological protection of the transplanted graft and decreased levels of caspase-3 and DNA fragmentation. The Tx + Z-VAD group showed the lowest levels of BT in all tissues. CONCLUSIONS: In small intestinal transplantation, both apoptosis and cell necrosis give rise to histological injury and BT. Apoptosis inhibition and necrosis inhibition treatments protect intestinal grafts from ischemia/reperfusion injury; Z-VAD supplementation has a greater effect on BT prevention than does administration of the PARS inhibitor 3-AB.

Administration of nitric oxide with caspase inhibitors minimizes bacterial translocation in experimental intestinal transplantation.

BACKGROUND: Bacterial translocation (BT) has been suggested to be responsible for the high incidence of infections occurring after small-bowel transplantation (Trp). Nitric oxide (NO) and apoptosis could affect cell demise. The aim of this study was to asses whether supplementation of University of Wisconsin (UW) solution with NO donors and apoptosis inhibitors can abolish BT in Trp. METHODS: The following experimental groups were studied: sham, Trp, intestinal transplantation, Trp+spermine NONOate (NONOs), and Trp+NONOs+caspase inhibitor Z-Val-Ala-Asp(Ome)-fluoromethylketone(Z-VAD-fmk). Histologic analysis, caspase-3 activity, DNA fragmentation, and BT from graft to mesenteric lymph nodes, liver, and spleen were measured in tissue samples after transplantation. RESULTS: During intestinal transplantation, apoptosis and necrosis were increased, showing graft injury and high levels of BT. The rats treated with NONOs showed a histologic protection of transplanted graft and a decrease in BT despite caspase-3 and DNA fragmentation-inducing effects. Administration of caspase inhibitor Z-VAD to NONOs-treated rats reversed the NO apoptosis-inducing effects and showed the lowest levels of BT in all tissues. CONCLUSIONS: Exogenous administration of NO associated with the inhibition of apoptosis maintains the graft in optimal conditions in terms of BT and improves the histology of the graft after intestinal transplantation in rats.

Long-term results of ileal pouch-anal anastomosis in Crohn's disease.

The unexpected diagnosis of Crohn's disease (CD) after restorative proctocolectomy is a relatively frequent occurrence. We report a retrospective analysis of the long-term development of patients with an ileal pouch-anal anastomosis (IPAA) in whom the definitive anatomopathological diagnosis was CD, and compare their development with that of patients in whom the diagnosis of ulcerative colitis (UC) was confirmed. We reviewed the clinical data of 112 patients with an IPAA. The definitive diagnosis was CD in 12, and UC in the rest. The mean follow-up period was 76 months (range 12 to 192). We analyzed and compared the epidemiologic and clinical data, postoperative complications, functional results, anxiety, and quality of life in the two groups. Postoperative morbidity and the degree of satisfaction were similar in the two groups. The test showed a lower level of anxiety and higher quality of life in patients with CD. Of all the functional parameters studied, only urgency of defecation presented a higher risk in the CD group (HR: 4.13, CI: 1.41-12.04, p = 0.027). Despite the fact that a diagnosis of CD is currently considered a contraindication for an IPAA, some patients with secondary diagnosis of CD have good functional outcome and quality of life after restorative proctocolectomy. Closure of the temporary ileostomy may be justified in these patients.

Protective effects of exogenous fructose-1,6-biphosphate during small bowel transplantation in rats.

BACKGROUND: We assessed the effect of adding exogenous fructose-1,6-biphosphate (F16BP) to the preservation solution (University of Wisconsin storage solution) used during an experimental procedure of small bowel transplantation in rats. METHODS: We studied levels of the nucleotides hypoxanthine/xanthine and adenosine in tissue after cold ischemia, as well as histologic changes and associated deleterious processes such as bacterial translocation produced by the reperfusion associated with the transplantation. RESULTS: The groups of rats treated with F16BP showed the lowest levels of hypoxanthine/xanthine and uric acid, the highest levels of adenosine, and the lowest levels of histologic damage and lactate dehydrogenase release to the bloodstream. Consumption of intestinal hypoxanthine during reperfusion was lowest in the groups treated with F16BP, as was the incidence of bacterial translocation. CONCLUSIONS: This study shows a protective effect of exogenous F16BP added to University of Wisconsin solution during experimental intestinal transplantation in rats. This protective effect, reflected by decreased intestinal damage and bacterial translocation, was related to a decrease in adenosine triphosphate depletion during cold ischemia before intestinal transplantation, and to the reduced availability of xanthine oxidase substrates for free radical generation during reperfusion.

Emergency operations for nondiverticular perforation of the left colon.

OBJECTIVE: Although diverticulitis is the most common cause of large bowel perforation, other disease may result in left colonic peritonitis. The aim of this study was to evaluate and compare the incidence, management, and outcome of patients with different causes of nondiverticular left colonic perforations. PATIENTS AND METHODS: From January 1992 to September 2000, 212 surgical patients underwent emergency operation for distal colonic peritonitis. Perforations were caused by diverticulitis in 133 patients (63%) and by a nondiverticular process in 79 (37%). Mortality and morbidity in patients with nondiverticular perforation of the distal large bowel its relationship with the general conditions, the grade and the cause of peritonitis were analysed. Four types of surgical procedures were used. Hartmann's procedure was performed in 40 patients (51%); intraoperative colonic lavage, resection, and primary anastomosis (ICL) in 27 patients (34%); colostomy in 7 (9%); and subtotal colectomy in 5 (6%). RESULTS: Perforated neoplasm, the most common cause of peritonitis, was observed in 30 patients, colonic ischemia in 20, iatrogenia in 13, and other causes in 16 patients. One or more complications were observed in 57 patients (72%); among causes of perforation, colonic ischemia was significantly associated with the longest hospital stay and highest mortality. Eighteen patients (23%) died. CONCLUSIONS: Left large bowel perforation by nondiverticular disease is associated with high mortality and morbidity. The prognosis of patients is determined by the development of septic shock and colonic ischemia, as underlying disease, may influence patient survival.

[Survival and recurrence in the multidisciplinary approach of colorectal cancer]. / Supervivencia y recidiva en el tratamiento multidisciplinario del carcinoma colorrectal.

BACKGROUND AND OBJECTIVE: Colorectal cancer is one of the most frequent causes of death in the general population. Our aim was to analyze our experience in the multidisciplinary approach of colorectal carcinoma during a three year period. PATIENTS AND METHOD: Between January 1996 and December 1998, we studied prospectively 807 patients with colorectal cancer. The epidemiology, treatment and outcome(recurrence and survival) were analyzed. The minimum follow-up was 3 years. RESULTS: There were 598 colon (65.5%) and 279 rectal (34.5%) tumors in all the series. Surgical treatment was elective in 84% and urgent in 16%, and was considered radical in 598 cases (74.1%). Chemotherapy or radiotherapy was administered in 49.6% and 18.3% patients, respectively. The overall 3-year survival was as follows: stage I 97.5%, stage II 90.6%, stage III 75.2%, and stage IV 12.6%. The 3-year free-disease survival was as follows: in colon cancer 97.8% for stage I, 87.3% for stage II, and 71.4% for stage III; and in rectal cancer 96.8% for stage I, 85.1% for stage II, and 75.4% for stage III. During the follow-up 124 patients (20.7%) developed recurrence: local (2.8%), systemic (15.9%) or both (2%). The three-year survival in operated patients with liver metastases was 61.9%. CONCLUSIONS: We have observed adequate survival and recurrence rates which are the result are of systematic protocols established by a multidisciplinary team.

Relationship between methylation and colonic inflammation in inflammatory bowel disease.

AIM: To investigate the relationship between the methylation status in the SLIT2 and TGFB2 promoters and colonic inflammation in inflammatory bowel disease patients. METHODS: We evaluated the methylation status of 2 genes (SLIT2 and TGFB2) in 226 biopsies taken from 62 colonoscopies of 38 patients (29 ulcerative colitis and 9 Crohn's colitis) using methylation-specific melting curve analysis. The relationships between methylation status and clinical, biological, endoscopic and histological activities were evaluated. Twenty-three of the 38 patients had a second colonoscopy and were included in a longitudinal analysis. Numerical results were given as the means ± SD of the sample and range, except when specified. Student t analysis, U Mann Whitney and ANOVA factor were used to compare the means. Qualitative results were based on the χ(2) test. RESULTS: SLIT2 methylation was more frequent in samples with endoscopic activity than with endoscopic remission (55% vs 18%, P < 0.001). SLIT2 methylation was also higher in samples with acute inflammation (56.5%) than in samples with chronic (24%) or absent inflammation (15%) (P < 0.001). For TGFB2 methylation, the correlation was only significant with endoscopic activity. Methylation was higher in the distal colon for both genes (P < 0.001 for SLIT2 and P = 0.022 for TGFB2). In the multivariate analysis, only inflammation status (and not disease duration or extension) was independently associated with SLIT2 methylation [OR = 6.6 (95%CI: 1.65-27.36), P = 0.009]. In the longitudinal analysis, the maintenance of endoscopic remission was protective for methylation. CONCLUSION: Endoscopic and histological inflammation are predictive for SLIT2 methylation.

Discovery and validation of new potential biomarkers for early detection of colon cancer.

BACKGROUND: Accurate detection of characteristic proteins secreted by colon cancer tumor cells in biological fluids could serve as a biomarker for the disease. The aim of the present study was to identify and validate new serum biomarkers and demonstrate their potential usefulness for early diagnosis of colon cancer. METHODS: The study was organized in three sequential phases: 1) biomarker discovery, 2) technical and biological validation, and 3) proof of concept to test the potential clinical use of selected biomarkers. A prioritized subset of the differentially-expressed genes between tissue types (50 colon mucosa from cancer-free individuals and 100 normal-tumor pairs from colon cancer patients) was validated and further tested in a series of serum samples from 80 colon cancer cases, 23 patients with adenoma and 77 cancer-free controls. RESULTS: In the discovery phase, 505 unique candidate biomarkers were identified, with highly significant results and high capacity to discriminate between the different tissue types. After a subsequent prioritization, all tested genes (N = 23) were successfully validated in tissue, and one of them, COL10A1, showed relevant differences in serum protein levels between controls, patients with adenoma (p = 0.0083) and colon cancer cases (p = 3.2e-6). CONCLUSION: We present a sequential process for the identification and further validation of biomarkers for early detection of colon cancer that identifies COL10A1 protein levels in serum as a potential diagnostic candidate to detect both adenoma lesions and tumor. IMPACT: The use of a cheap serum test for colon cancer screening should improve its participation rates and contribute to decrease the burden of this disease.

Novel methylation panel for the early detection of neoplasia in high-risk ulcerative colitis and Crohn's colitis patients.

BACKGROUND: Patients with ulcerative colitis and Crohn's colonic disease are at increased risk of developing colorectal cancer (CRC). The aim of the study was to analyze the methylation status of selected genes as a risk marker for CRC in inflammatory bowel disease (IBD) patients. METHODS: We evaluated the methylation status of four genes (TGFB2, SLIT2, HS3ST2, and TMEFF2) in biopsies of four groups of patients: 60 patients with sporadic CRC, 32 patients with IBD-associated neoplasia, 85 patients with IBD without associated neoplasia (20 at high risk and 65 at low risk), and 28 healthy controls. Methylation-specific melting curve analysis (MS-MCA) was used. Methylation status of these genes was also assessed in stool DNA from 60 IBD patients without neoplasia. RESULTS: Methylation of the panel of genes analyzed was a very common phenomenon (78%) in IBD-associated neoplasia. The prevalence of methylation in adjacent nonneoplastic mucosa was also high (12/30). This prevalence was higher than in mucosa from healthy controls (2/28;7.1%; P < 0.05). Methylation of SLIT2 and TMEFF2 was more frequently detected in the mucosa of IBD patients at high risk of dysplasia or cancer (15/20) than patients at low risk (32/63) (P = 0.05 and P = 0.03, respectively). When stool samples were assessed, only SLIT2 gene methylation was more frequently methylated in the group of patients at high risk of dysplasia or cancer (4/16) compared to low risk (0/37) (P = 0.006). CONCLUSIONS: Analysis of a panel of methylation markers may help in the early identification of colorectal dysplasia or cancer in high-risk IBD patients.

DNA methylation biomarkers for noninvasive diagnosis of colorectal cancer.

DNA methylation biomarkers for noninvasive diagnosis of colorectal cancer (CRC) and precursor lesions have been extensively studied. Different panels have been reported attempting to improve current protocols in clinical practice, although no definite biomarkers have been established. In the present study, we have examined patient biopsies starting from a comprehensive analysis of DNA methylation differences between paired normal and tumor samples in known cancer-related genes aiming to select the best performing candidates informative for CRC diagnosis in stool samples. Five selected markers were considered for subsequent analyses in independent biologic cohorts and in silico data sets. Among the five selected genes, three of them (AGTR1, WNT2 and SLIT2) were validated in stool DNA of affected patients with a detection sensitivity of 78% [95% confidence interval (CI), 56%-89%]. As a reference, DNA methylation of VIM and SEPT9 was evaluated in a subset of stool samples yielding sensitivities of 55% and 20%, respectively. Moreover, our panel may complement histologic and endoscopic diagnosis of inflammatory bowel disease (IBD)-associated neoplasia, as it was also efficient detecting aberrant DNA methylation in non-neoplastic tissue samples from affected patients. This novel panel of specific methylation markers can be useful for early diagnosis of CRC using stool DNA and may help in the follow-up of high-risk patients with IBD.

Novel methylation panel for the early detection of colorectal tumors in stool DNA.

BACKGROUND: Previous studies showed that the assessment of promoter hypermethylation of a limited number of genes in tumor biopsies may identify the majority of colorectal tumors. This study aimed to assess the clinical usefulness of a panel of methylation biomarkers in stool DNA in the identification of colorectal tumors, using methylation-specific melting curve analysis (MS-MCA), a technique that simultaneously analyzes all cytosine-phosphate-guanine (CpG) residues within a promoter. MATERIALS AND METHODS: The promoter methylation status of 4 tumor-related genes (RARB2, p16INK4a, MGMT, and APC) was analyzed in DNA stool samples and corresponding tissues in an initial set of 12 patients with newly diagnosed primary colorectal carcinomas and 20 patients with newly diagnosed colorectal adenomas, using methylation-specific polymerase chain reaction. Results were replicated in a set of 82 patients (20 healthy subjects, 16 patients with inflammatory bowel disease (IBD), 20 patients with adenomas, and 26 patients with carcinomas), using MS-MCA analyses. RESULTS: In the initial set, >or= 1 positive methylation marker was detected in the stools of 9 of 12 patients (75%) with carcinomas and 12 of 20 patients (60%) with adenomas, with no false-positive results. Stool analyses missed 7 methylated lesions (25%). In the replication set, stool DNA testing detected 16 of 26 carcinomas (62%) and 8 of 20 adenomas (40%). The MS-MCAs missed 14 methylated tumors (37%). No aberrant methylation was evident in healthy subjects, but the RARB2 marker was positive in 2 of 15 stool samples (13%) of patients with IBD. CONCLUSION: Analysis via MS-MCA of a panel of methylation markers in stool DNA may offer a good alternative in the early, noninvasive detection of colorectal tumors.

Caspase-3 activity, response to chemotherapy and clinical outcome in patients with colon cancer.

BACKGROUND AND AIMS: The prognostic value of the degree of apoptosis in colorectal cancer is controversial. This study evaluates the putative clinical usefulness of measuring caspase-3 activity as a prognostic factor in colonic cancer patients receiving 5-fluoracil adjuvant chemotherapy. MATERIALS AND METHODS: We evaluated caspase-3-like protease activity in tumours and in normal colon tissue. Specimens were studied from 54 patients. These patients had either stage III cancer (Dukes stage C) or high-risk stage II cancer (Dukes stage B2 with invasion of adjacent organs, lymphatic or vascular infiltration or carcinoembryonic antigen [CEA] >5). Median follow-up was 73 months. Univariate analysis was performed previously to explore the relation of different variables (age, sex, preoperative CEA, tumour size, Dukes stage, vascular invasion, lymphatic invasion, caspase-3 activity in tumour and caspase-3 activity in normal mucosa) as prognostic factors of tumour recurrence after chemotherapy treatment. Subsequently, a multivariate Cox regression model was performed. RESULTS: Median values of caspase-3 activity in tumours were more than twice those in normal mucosa (88.1 vs 40.6 U, p=0.001), showing a statistically significant correlation (r=0.34). Significant prognostic factors of recurrence in multivariate analysis were: male sex (odds ratio, OR=3.53 [1.13-10.90], p=0.02), age (OR=1.09 [1.01-1.18], p=0.03), Dukes stage (OR=1.93 [1.01-3.70]), caspase-3 activity in normal mucosa (OR=1.02 [1.01-1.04], p=0.017) and caspase-3 activity in tumour (OR=1.02 [1.01-1.03], p=0.013). CONCLUSION: Low caspase-3 activity in the normal mucosa and tumour are independent prognostic factors of tumour recurrence in patients receiving adjuvant 5-fluoracil-based treatment in colon cancer, correlating with poor disease-free survival and higher recurrence rate.

[Long-term results of emergency surgery for colon cancer compared with elective surgery]. / Resultados a largo plazo de la cirugía urgente y electiva del cáncer de colon. Estudio comparativo.

INTRODUCTION: Currently, the mechanisms that worsen the prognosis of complicated colon cancers are still not well known. Moreover, the possible effect of using sound oncological principles in emergency surgery on long-term prognosis has not been studied in detail. AIMS: The aim of the present study was to analyze the 5-year efficacy of curative oncological surgery for complicated colon cancer performed in an emergency setting in terms of tumor recurrence and survival compared with elective surgery of uncomplicated tumors. PATIENTS AND METHOD: We performed a prospective observational cohort study in patients who underwent emergency surgery for complicated colon cancer (group 1) and patients who underwent elective surgery (group 2). Exclusion criteria were tumors of less than 15 cm from the anal verge, palliative surgery, and distant metastases. RESULTS: During the study period, 646 patients underwent surgery: there were 165 (25.5%) emergency surgeries and 481 (74.5%) elective interventions. Surgery was considered curative in 456 (70.6%) patients: 102 (22.4%) emergency and 354 (77.6%) elective surgeries. Significant differences were found in disease stage between the 2 groups (P = 0.003). The postoperative mortality rate was 12.7% in group 1 and 3.4% in group 2 (P = 0.001). When patients were stratified by TNM stage, worse 5-year cancer-related and disease-free survival rates were observed in group 1 patients with stage II tumors. No differences were found in cancer-related survival rates in stage III patients (P = 0.178). There were no significant differences in overall survival, cancer-related survival or tumor recurrence rates when group 1 was compared with a subgroup of patients in group 2 with factors of poor prognosis. CONCLUSIONS: Complicated colon cancer presents in more advanced stages and had a worse overall long-term prognosis than uncomplicated tumour. These differences decrease when patients are subclassified by tumoral stage. Overall survival and cancer-related survival rates similar to those of elective surgery can be achieved in emergency surgery when curative oncological resection is performed.