Sporadic Colorectal Neoplasia Research Articles

Anti-tumor effects of an ID antagonist with no observed acquired resistance

ID proteins are helix-loop-helix (HLH) transcriptional regulators frequently overexpressed in cancer. ID proteins inhibit basic-HLH transcription factors often blocking differentiation and sustaining proliferation. A small-molecule, AGX51, targets ID proteins for degradation and impairs ocular neovascularization in mouse models. Here we show that AGX51 treatment of cancer cell lines impairs cell growth and viability that results from an increase in reactive oxygen species (ROS) production upon ID degradation. In mouse models, AGX51 treatment suppresses breast cancer colonization in the lung, regresses the growth of paclitaxel-resistant breast tumors when combined with paclitaxel and reduces tumor burden in sporadic colorectal neoplasia. Furthermore, in cells and mice, we fail to observe acquired resistance to AGX51 likely the result of the inability to mutate the binding pocket without loss of ID function and efficient degradation of the ID proteins. Thus, AGX51 is a first-in-class compound that antagonizes ID proteins, shows strong anti-tumor effects and may be further developed for the management of multiple cancers.

Eicosapentaenoic acid and aspirin, alone and in combination, for the prevention of colorectal adenomas (seAFOod Polyp Prevention trial): a multicentre, randomised, double-blind, placebo-controlled, 2 × 2 factorial trial

SummaryBackgroundThe omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) and aspirin both have proof of concept for colorectal cancer chemoprevention, aligned with an excellent safety profile. Therefore, we aimed to test the efficacy of EPA and aspirin, alone and in combination and compared with a placebo, in individuals with sporadic colorectal neoplasia detected at colonoscopy.MethodsIn a multicentre, randomised, double-blind, placebo-controlled, 2 × 2 factorial trial, patients aged 55–73 years who were identified during colonoscopy as being at high risk in the English Bowel Cancer Screening Programme (BCSP; ≥3 adenomas if at least one was ≥10 mm in diameter or ≥5 adenomas if these were <10 mm in diameter) were recruited from 53 BCSP endoscopy units in England, UK. Patients were randomly allocated (1:1:1:1) using a secure web-based server to receive 2 g EPA-free fatty acid (FFA) per day (either as the FFA or triglyceride), 300 mg aspirin per day, both treatments in combination, or placebo for 12 months using random permuted blocks of randomly varying size, and stratified by BCSP site. Research staff and participants were masked to group assignment. The primary endpoint was the adenoma detection rate (ADR; the proportion of participants with any adenoma) at 1 year surveillance colonoscopy analysed in all participants with observable follow-up data using a so-called at-the-margins approach, adjusted for BCSP site and repeat endoscopy at baseline. The safety population included all participants who received at least one dose of study drug. The trial is registered with the International Standard Randomised Controlled Trials Number registry, number ISRCTN05926847.FindingsBetween Nov 11, 2011, and June 10, 2016, 709 participants were randomly assigned to four treatment groups (176 to placebo, 179 to EPA, 177 to aspirin, and 177 to EPA plus aspirin). Adenoma outcome data were available for 163 (93%) patients in the placebo group, 153 (85%) in the EPA group, 163 (92%) in the aspirin group, and 161 (91%) in the EPA plus aspirin group. The ADR was 61% (100 of 163) in the placebo group, 63% (97 of 153) in the EPA group, 61% (100 of 163) in the aspirin group, and 61% (98 of 161) in the EPA plus aspirin group, with no evidence of any effect for EPA (risk ratio [RR] 0·98, 95% CI 0·87 to 1·12; risk difference −0·9%, −8·8 to 6·9; p=0·81) or aspirin (RR 0·99 (0·87 to 1·12; risk difference −0·6%, −8·5 to 7·2; p=0·88). EPA and aspirin were well tolerated (78 [44%] of 176 had ≥1 adverse event in the placebo group compared with 82 [46%] in the EPA group, 68 [39%] in the aspirin group, and 76 [45%] in the EPA plus aspirin group), although the number of gastrointestinal adverse events was increased in the EPA alone group at 146 events (compared with 85 in the placebo group, 86 in the aspirin group, and 68 in the aspirin plus placebo group). Six upper-gastrointestinal bleeding events were reported across the treatment groups (two in the EPA group, three in the aspirin group, and one in the placebo group).InterpretationNeither EPA nor aspirin treatment were associated with a reduction in the proportion of patients with at least one colorectal adenoma. Further research is needed regarding the effect on colorectal adenoma number according to adenoma type and location. Optimal use of EPA and aspirin might need a precision medicine approach to adenoma recurrence.FundingEfficacy and Mechanism Evaluation Programme, a UK Medical Research Council and National Institute for Health Research partnership.

Dynamics of Genome Alterations in Crohn's Disease-Associated Colorectal Carcinogenesis.

Purpose: Patients with inflammatory bowel diseases, that is, ulcerative colitis and Crohn's disease (CD), face an increased risk of developing colorectal cancer (CRC). Evidence, mainly from ulcerative colitis, suggests that TP53 mutations represent an initial step in the progression from inflamed colonic epithelium to CRC. However, the pathways involved in the evolution of CRC in patients with CD are poorly characterized.Experimental Design: Here, we analyzed 73 tissue samples from 28 patients with CD-CRC, including precursor lesions, by targeted next-generation sequencing of 563 cancer-related genes and array-based comparative genomic hybridization. The results were compared with 24 sporadic CRCs with similar histomorphology (i.e., mucinous adenocarcinomas), and to The Cancer Genome Atlas data (TCGA).Results: CD-CRCs showed somatic copy-number alterations (SCNAs) similar to sporadic CRCs with one notable exception: the gain of 5p was significantly more prevalent in CD-CRCs. CD-CRCs had a distinct mutation signature: TP53 (76% in CD-CRCs vs. 33% in sporadic mucinous CRCs), KRAS (24% vs. 50%), APC (17% vs. 75%), and SMAD3 (3% vs. 29%). TP53 mutations and SCNAs were early and frequent events in CD progression, while APC, KRAS, and SMAD2/4 mutations occurred later. In four patients with CD-CRC, at least one mutation and/or SCNAs were already present in non-dysplastic colonic mucosa, indicating occult tumor evolution.Conclusions: Molecular profiling of CD-CRCs and precursor lesions revealed an inflammation-associated landscape of genome alterations: 5p gains and TP53 mutations occurred early in tumor development. Detection of these aberrations in precursor lesions may help predicting disease progression and distinguishes CD-associated from sporadic colorectal neoplasia. Clin Cancer Res; 24(20); 4997-5011. ©2018 AACR.

Mitotic and apoptotic activity in colorectal neoplasia

BackgroundColorectal cancer (CRC) is third most commonly diagnosed cancer worldwide. The aim of the prospective study was to evaluate mitosis and apoptosis of epithelial cells at each stage of colorectal neoplasia.MethodsA total of 61 persons were enrolled into the study: 18 patients with non-advanced colorectal adenoma (non-a-A), 13 patients with advanced colorectal adenoma (a-A), 13 patients with CRC and 17 controls: individuals with normal findings on colonoscopy. Biopsy samples were taken from pathology (patients) and healthy mucosa (patients and healthy controls). Samples were formalin-fixed paraffin-embedded and stained with haematoxylin-eosin. Mitotic and apoptotic activity were evaluated in lower and upper part of the crypts and in the superficial compartment. Apoptotic activity was also assessed using detection of activated caspase-3.ResultsIn controls, mitotic activity was present in lower part of crypts, accompanied with low apoptotic activity. Mitotic and apoptotic activity decreased (to almost zero) in upper part of crypts. In superficial compartment, increase in apoptotic activity was observed. Transformation of healthy mucosa into non-a-A was associated with significant increase of mitotic activity in lower and upper part of the crypts and with significant increase of apoptotic activity in all three compartments; p < 0.05. Transformation of non-a-A into a-A did not lead to any further significant increase in apoptotic activity, but was related to significant increase in mitotic activity in upper part of crypts and superficial compartment. A significant decrease in apoptotic activity was detected in all three comparments of CRC samples compared to a-A; p < 0.05. No differences in mitotic and apoptotic activity between biopsies in healthy controls and biopsy samples from healthy mucosa in patients with colorectal neoplasia were observed. Detection of activated caspase-3 confirmed the above findings in apoptotic activity.ConclusionsSignificant dysregulation of mitosis and apoptosis during the progression of colorectal neoplasia, corresponding with histology, was confirmed. In patients with sporadic colorectal neoplasia, healthy mucosa does not display different mitotic and apoptotic activity compared to mucosa in healthy controls and therefore adequate endoscopic/surgical removal of colorectal neoplasia is sufficient.

Comparative analysis of copy number variations in ulcerative colitis associated and sporadic colorectal neoplasia.

BackgroundThe incidence of and mortality from colorectal cancers (CRC) can be reduced by early detection. Currently there is a lack of established markers to detect early neoplastic changes. We aimed to identify the copy number variations (CNVs) and the associated genes which could be potential markers for the detection of neoplasia in both ulcerative colitis-associated neoplasia (UC-CRN) and sporadic colorectal neoplasia (S-CRN).MethodsWe employed array comparative genome hybridization (aCGH) to identify CNVs in tissue samples of UC nonprogressor, progressor and sporadic CRC. Select genes within these CNV regions as a panel of markers were validated using quantitative real time PCR (qRT-PCR) method along with the microsatellite instability (MSI) in an independent cohort of samples. Immunohistochemistry (IHC) analysis was also performed.ResultsIntegrated analysis showed 10 overlapping CNV regions between UC-Progressor and S-CRN, with the 8q and 12p regions showing greater overlap. The qRT-PCR based panel of MYC, MYCN, CCND1, CCND2, EGFR and FNDC3A was successful in detecting neoplasia with an overall accuracy of 54 % in S-CRN compared to that of 29 % in UC neoplastic samples. IHC study showed that p53 and CCND1 were significantly overexpressed with an increasing frequency from pre-neoplastic to neoplastic stages. EGFR and AMACR were expressed only in the neoplastic conditions.ConclusionCNVs that are common and unique to both UC-associated and sporadic colorectal neoplasm could be the key players driving carcinogenesis. Comparative analysis of CNVs provides testable driver aberrations but needs further evaluation in larger cohorts of samples. These markers may help in developing more effective neoplasia-detection strategies during screening and surveillance programs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2303-4) contains supplementary material, which is available to authorized users.

Su2013 Methylated DNA Markers for Detection of Sporadic Colorectal Neoplasia: Comparison Between Age Groups Younger Than and Older Than 50

Su2013 Methylated DNA Markers for Detection of Sporadic Colorectal Neoplasia: Comparison Between Age Groups Younger Than and Older Than 50

Cytokine gene polymorphisms, cytokine levels and the risk of colorectal neoplasia in a screened population of Northeast Scotland.

Cytokine gene polymorphisms modify expression and their circulating protein levels reflect inflammatory response. Chronic inflammation plays a key role in the pathogenesis of colorectal neoplasia (CRN) associated with inflammatory bowel disease, but it is not clear whether inflammation is a cause or an effect of tumours in sporadic CRN. We therefore investigated the association of cytokine gene polymorphisms and circulating cytokine levels on the risk of CRN in Northeast Scotland, which has a high incidence of CRN. We recruited two groups of patients from a screening colonoscopy cohort, either preprocedure or 3-24 months postprocedure. Participants with CRN were compared with participants with no evidence of CRN (controls). Blood-derived DNA was used to genotype polymorphisms in IL1B, IL1-RN, IL6, IL8, IL10, PTGS2 and TNFA genes. Circulating levels of high-sensitivity C-reactive protein and six cytokines [interleukin-1β (IL-1β), IL-4, IL-6, IL-8, IL-10 and tumour necrosis factor-α (TNF-α)] were measured. To examine the effect of CRN resection on marker levels, we used propensity score matching. A total of 884 patients were eligible for analysis, including 388 CRN cases and 496 controls. Cases were older (mean age 64 vs. 62 years, P<0.01) and more likely to be men (67 vs. 55%, P<0.001). Controls were more likely to be regular users of NSAID (P<0.0001). Compared with homozygous carriage of respective common alleles, proinflammatory CC genotypes of IL1B-31C>T [odds ratio (OR) (95% confidence interval (CI) 1.68 (1.03-2.73)] and PTGS2-765 C>G [OR (95% CI) 2.97 (1.05-8.46)] were each associated with an increased risk of CRN. Conversely, carriage of the A allele of IL8-251A>T was associated with a lower risk of CRN compared with the TT genotype [ORs (95% CI) 0.60 (0.41-0.86) for heterozygous, 0.88 (0.57-1.37) for homozygous, and 0.68 (0.48-0.95) for heterozygous and homozygous combined]. Compared with postprocedure cases, IL8, TNF-α and C-reactive protein levels were significantly higher in preprocedure cases, but IL4 and IL10 protein levels were significantly lower. Proinflammatory cytokine gene polymorphisms in IL1B-31 and PTGS2-765 increase the risk of developing CRN. Levels of proinflammatory IL8, TNF-α and C-reactive protein markers are significantly higher while CRN is in situ. Along with the NSAID findings, these data point to inflammation as an underlying pathogenetic mechanism in CRN.

Immunohistochemical expression of SP-NK-1R-EGFR pathway and VDR in colonic inflammation and neoplasia.

To determine the expression of neurokinin-1 receptor (NK-1R), phosphorylated epidermal growth factor receptor (pEGFR), cyclooxygenase-2 (Cox-2), and vitamin D receptor (VDR) in normal, inflammatory bowel disease (IBD), and colorectal neoplasia tissues from Puerto Ricans. Tissues from patients with IBD, colitis-associated colorectal cancer (CAC), sporadic dysplasia, and sporadic colorectal cancer (CRC), as well as normal controls, were identified at several centers in Puerto Rico. Archival formalin-fixed, paraffin-embedded tissues were de-identified and processed by immunohistochemistry for NK-1R, pEGFR, Cox-2, and VDR. Pictures of representative areas of each tissues diagnosis were taken and scored by three observers using a 4-point scale that assessed intensity of staining. Tissues with CAC were further analyzed by photographing representative areas of IBD and the different grades of dysplasia, in addition to the areas of cancer, within each tissue. Differences in the average age between the five patient groups were assessed with one-way analysis of variance and Tukey-Kramer multiple comparisons test. The mean scores for normal tissues and tissues with IBD, dysplasia, CRC, and CAC were calculated and statistically compared using one-way analysis of variance and Dunnett's multiple comparisons test. Correlations between protein expression patterns were analyzed with the Pearson's product-moment correlation coefficient. Data are presented as mean ± SE. On average, patients with IBD were younger (34.60 ± 5.81) than normal (63.20 ± 6.13, P < 0.01), sporadic dysplasia (68.80 ± 4.42, P < 0.01), sporadic cancer (74.80 ± 4.91, P < 0.001), and CAC (57.50 ± 5.11, P < 0.05) patients. NK-1R in cancer tissue (sporadic CRC, 1.73 ± 0.34; CAC, 1.57 ± 0.53) and sporadic dysplasia (2.00 ± 0.45) were higher than in normal tissues (0.73 ± 0.19). pEGFR was significantly increased in sporadic CRC (1.53 ± 0.43) and CAC (2.25 ± 0.47) when compared to normal tissue (0.07 ± 0.25, P < 0.05, P < 0.001, respectively). Cox-2 was significantly increased in sporadic colorectal cancer (2.20 ± 0.23 vs 0.80 ± 0.37 for normal tissues, P < 0.05). In comparison to normal (2.80 ± 0.13) and CAC (2.50 ± 0.33) tissues, VDR was significantly decreased in sporadic dysplasia (0.00 ± 0.00, P < 0.001 vs normal, P < 0.001 vs CAC) and sporadic CRC (0.47 ± 0.23, P < 0.001 vs normal, P < 0.001 vs CAC). VDR levels negatively correlated with NK-1R (r = -0.48) and pEGFR (r = -0.56) in normal, IBD, sporadic dysplasia and sporadic CRC tissue, but not in CAC. Immunohistochemical NK-1R and pEGFR positivity with VDR negativity can be used to identify areas of sporadic colorectal neoplasia. VDR immunoreactivity can distinguish CAC from sporadic cancer.

LINE-1 hypomethylation is neither present in rectal aberrant crypt foci nor associated with field defect in sporadic colorectal neoplasia.

BackgroundAberrant crypt foci (ACF) are considered the first identifiable preneoplastic lesion in colorectal cancer (CRC), and have been proposed as a potential biomarker for CRC risk. Global DNA hypomethylation is an early event in colorectal carcinogenesis, and long interspersed nuclear element-1 (LINE-1) methylation status is a well-known surrogate marker for genome-wide DNA methylation levels. Despite the gradual increase in DNA hypomethylation in the adenoma–carcinoma sequence, LINE-1 methylation in ACF has never been studied. Moreover, recent studies have reported a field defect for LINE-1 hypomethylation, suggesting that LINE-1 methylation status in normal mucosa could be used to stratify CRC risk and tailor preventive strategies. Thus, we assessed LINE-1 status by pyrosequencing in rectal ACF and paired normal colorectal mucosa from individuals with sporadic colon cancer (CC) (n = 35) or adenoma (n = 42), and from healthy controls (n = 70).FindingsCompared with normal mucosa, LINE-1 in ACF were hypermethylated across all groups (P < 0.0001). Furthermore, LINE-1 methylation status in normal colorectal mucosa was independent of the presence of adenoma or CC (P = 0.1072), and did not differ depending on the distance to the adenoma or CC. Interestingly, when we compared the LINE-1 methylation status in normal mucosa from different segments of the colorectum, we found higher hypomethylation in the rectum compared with the descending colon (P < 0.0001).ConclusionsOverall, our results suggest that global hypomethylation is not present in rectal ACF and argues against the existence of LINE-1 methylation field defect in sporadic colon cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/1868-7083-6-24) contains supplementary material, which is available to authorized users.

Duodenal Adenomas Coincide with Colorectal Neoplasia

Small case series have alluded to an association between sporadic duodenal adenomas and colorectal neoplasia. The strength of the association remains uncertain. This case-control study was designed to test this association in a large national pathology database. This study, performed at Miraca Life Sciences, a specialized pathology laboratory that receives gastrointestinal biopsy specimens from outpatient centers throughout the US, included all subjects who underwent a bidirectional endoscopy with biopsy results from both procedures between January 2008 and December 2011. The association between duodenal and colonic neoplasms was investigated using odds ratios (OR) and their 95 % confidence intervals (CIs) derived from univariate and multivariate analyses. There were 203,277 patients who underwent bidirectional procedures within the study period (mean age 58 years, 58 % females). Duodenal adenomas were present in 537 patients (median age 65 years, 51 % females; OR for male sex 1.34, 95 % CI 1.13-1.59). Hyperplastic colon polyps were present in 30,205 and colon adenomas in 85,801 patients. Hyperplastic polyps were more common in patients with duodenal adenomas (1.45, 1.07-1.95). Patients with duodenal adenomas also had a significantly greater prevalence of all types of colonic adenomas (2.65, 2.16-3.25), particularly of advanced adenomas (4.30, 3.24-5.70) and colorectal cancer (3.13, 1.38-7.12). Duodenal adenomas were associated with an equally increased risk for left and right colon adenomas. Patients with duodenal adenomas harbor an increased risk for any type of colonic neoplasm. This association may provide new insights into the general mechanisms underlying mucosal proliferation in the gastrointestinal tract.

Circulating MicroRNAs as Biomarkers of Colorectal Cancer: Results From a Genome-Wide Profiling and Validation Study

Circulating microRNAs (miRNAs/miRs) might be used as biomarkers for the diagnosis of cancer and other diseases. Noninvasive approaches are needed to complement and improve upon current strategies for colorectal cancer (CRC) screening. We investigated whether plasma levels of miRNA can differentiate patients with CRC from healthy individuals. We also investigated whether plasma samples from patients with premalignant neoplastic lesions, such as advanced adenomas (AAs), also had a different expression pattern of miRNAs. We analyzed 196 plasma samples from 123 patients newly diagnosed with sporadic colorectal neoplasia (63 with CRC and 60 with AAs) and 73 healthy individuals (controls) seen at 2 tertiary medical centers in Spain. An initial set of samples was analyzed using a genome-wide miRNA expression profiling assay (n = 61). Quantitative reverse-transcription PCR was used to validate the expression of selected miRNAs in an independent cohort (n = 135). Patients with CRC or AAs had plasma miRNA expression profiles that differed significantly from those of controls. We selected a group of 13 miRNAs for validation in an independent cohort of patients; 6 (miR18a, miR19a, miR19b, miR15b, miR29a, and miR335) were confirmed to be significantly up-regulated in patients with CRC, differentiating patients with CRC from controls with area under the receiver operating characteristic curve values ranging from 0.80 (95% confidence interval [CI], 0.71-0.89) to 0.70 (95% CI, 0.59-0.80). Only miR18a was confirmed to be significantly up-regulated in patients with AAs, compared with controls; the area under the receiver operating characteristic curve value was 0.64 (95% CI, 0.52-0.75). Patients with CRC have significantly different patterns of miRNA expression than healthy individuals. These patterns might be developed as biomarkers for CRC, although they have limited value in identifying patients with premalignant neoplastic lesions.

Molecular alterations in colitis-associated colorectal neoplasia: Study from a low prevalence area using magnifying chromo colonoscopy

Background and aimLongstanding ulcerative colitis (UC) predisposes to colorectal cancer (CRC). To understand the molecular pathogenesis of colitis-associated colorectal neoplasia (UC-CRN), we studied the frequency of microsatellite instability (MSI) and mutations in p53, BRAF and KRAS genes in the tissues of patients with long standing UC with or without neoplasia and compared them with colitis patients without risk of neoplasia, and those with sporadic colorectal neoplasia (S-CRN) in an area with lower prevalence for either disease. MethodsBiopsies were obtained during magnifying chromo colonoscopy or routine colonoscopy in consecutive UC patients with high risk (UC-HR) and low risk (UC-LR) of neoplasia, and those with S-CRN. MSI (NCI-Bethesda panel) and mutations in p53, KRAS and BRAF genes were analysed. ResultsTwenty-eight patients with UC-HR, 30 with UC-LR and 30 with S-CRN were included. Six (21.4%) of UC-HR had neoplasia (Progressors). MSI was not detected in the UC-CRN group as compared to 5 (16.7%) in the S-CRN group. p53 mutations occurred in 1 (3.3%) of UC-LR, increasing to 6 (27.3%, P<0.05) and 3 (50%, P<0.05) in the UC-HR subgroups without and with neoplasia respectively, as against 10 (33.3%) in sporadic neoplasia group. KRAS mutations were found only in the presence of neoplasia. None showed the BRAF mutation. ConclusionsIn a population with a lower prevalence for UC and CRC, the molecular pathogenesis of colitis-associated colorectal neoplasia is comparable to that reported from areas with a higher prevalence of these diseases, MSI being an exception.

Progression of low-grade dysplasia in ulcerative colitis: effect of colonic location

Emerging evidence suggests that the biology of sporadic colorectal neoplasia may differ between the proximal and distal colon. Whether such a difference exists in colitis-associated colorectal neoplasia is unknown. To compare the rate of progression to advanced neoplasia (AN) between proximal and distal dysplasia in patients with ulcerative colitis (UC). Retrospective cohort study. Tertiary medical center. From an institutional database of more than 700 patients with UC who underwent 2 or more surveillance colonoscopies between 1994 and 2006, we identified patients with extensive UC and low-grade dysplasia (LGD). Neoplasia proximal to the splenic flexure was considered proximal. Progression to AN, defined as high-grade dysplasia (HGD) or colorectal cancer (CRC). Among 121 patients with LGD, all 7 who progressed to CRC and 6 of 8 who progressed to HGD had distal LGD initially. Subjects with distal LGD had a significantly shorter time to progression than those with proximal LGD (P = .019); 5-year AN-free survivals for distal and proximal LGD were 75 ± 7% and 95 ± 3%, respectively (hazard ratio [HR] 5.0; 95% CI, 1.1-22.0). Additionally, flat LGD was significantly more likely to progress than raised LGD on univariate testing (HR 3.6; 95% CI, 1.3-10.1). Neither morphology nor sidedness remained significant in multivariable testing, although there was little change in the HRs (HR 2.4; 95% CI, 0.8-7.1 for morphology; HR 3.5; 95% CI, 0.7-16.8 for sidedness) in proportional hazards modeling. Nonrandomized, retrospective trial and low incidence of AN. In patients with long-standing, extensive UC, distal LGD is more common and progresses more rapidly to AN than proximal LGD.

Chemoprevention of colorectal cancer in inflammatory bowel disease

The risk of developing colorectal cancer is increased in patients with inflammatory bowel disease (IBD). Surveillance colonoscopy has not been shown to prolong survival and rates of interval cancer are reported to be high. Various chemopreventive agents have been clearly shown to reduce the risk of colorectal adenoma and cancer in the general population and the problems associated with colonoscopic surveillance have led to increasing interest in utilising chemopreventive strategies to reduce the risk of colorectal cancer in patients with inflammatory bowel disease as well. Continuing colonic inflammation has been shown to be important in the development of colorectal cancer and therefore anti-inflammatory agents have been considered potential chemopreventive agents. As present no agents have been shown to have indisputable chemopreventive activity in IBD but 5-ASAs and thiopurine analogues by reducing inflammation are likely to have some chemopreventive activity and will often be indicated for disease control. More studies are needed using agents such as aspirin and calcium which have been shown to be chemopreventive in sporadic colorectal neoplasia.

5-Aminosalicylic acid inhibits colitis-associated but not sporadic colorectal neoplasia in a novel conditional Apc mouse model

Genetic predisposition, life-style habits and inflammatory bowel diseases (IBD)-related colitis are a main risk factor for colorectal cancer (CRC). 5-Aminosalicylic acid (5-ASA, mesalazine) is a mainstay therapy in IBD and believed to reduce the risk for developing CRC. We aimed to determine the ability of 5-ASA enemas to inhibit the development of sporadic and colitis-related neoplasia in mice. FabplCre;Apc(15lox/+) mice, which spontaneously develop sporadic colorectal tumours, were treated at 5 weeks of age with 5-ASA or placebo enemas for 3 weeks and examined for colorectal tumourigenesis at 8 weeks of age. Colitis-related tumour development was investigated in these mice by administration of dextran sodium sulphate, inducing intestinal inflammation and accelerating colorectal tumourigenesis, combined with treatment of 5-ASA or placebo enemas during and/or after colitis induction. 5-ASA significantly reduced colitis-accelerated neoplasia development by 50%, from 19.4 +/- 2.7 to 9.4 +/- 2.4 (mean tumour numbers +/- SEM, P = 0.02), in the distal part of the large intestine covered by the enema. 5-ASA was only effective when given during and/or after the intestinal inflammatory period. 5-ASA did not reduce, however, sporadic neoplasia development in the FabplCre;Apc(15lox/+) mice. 5-ASA tended to reduce proliferation of epithelial cells in the colitis-associated colorectal tumours but not in the sporadic colorectal tumours. In conclusion, 5-ASA medication inhibits the development of colitis-associated tumours in FabplCre;Apc(15lox/+) mice when administered during and/or after the induction of inflammation. 5-ASA does not reduce, however, sporadic tumour development in this mouse model.

S1996 Role of Chronic Inflammation in Sporadic Colorectal Neoplasia

S1996 Role of Chronic Inflammation in Sporadic Colorectal Neoplasia

Inhibitory effects of the cyclooxygenase-2 inhibitor, etodolac, on colitis-associated tumorigenesis in p53-deficient mice treated with dextran sulfate sodium

Non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors are representative agents for the chemoprevention of sporadic colorectal neoplasia. However, few reports have described the chemopreventive effects of such agents on colitis-associated tumorigenesis. To clarify whether treatment with the COX-2 inhibitor may reduce the risk of colitis-associated neoplasia, we investigated the effect of one such agent, etodolac, on tumorigenesis in the colitis-associated neoplasia model using p53-deficient mice treated with dextran sulfate sodium (DSS). The p53-/- mice were divided into four groups: i) treatment with DSS + etodolac, then after two cycles of DSS, the mice were given distilled water for 84 days. In addition, etodolac was administered three times a week at a dose of 10 mg/kg body weight throughout the experiment. ii) Treatment with two cycles of DSS only, followed by distilled water for 84 days. iii) Treatment with etodolac alone. iv) Distilled water alone was administered to the control group. The incidence of mice with neoplasia was 82.4% in the DSS + etodolac group and 100% in the DSS-alone group. No neoplasia was observed in the etodolac-alone and control groups. The mean (+/- SEM) number of total neoplasias per mouse was 1.29+/-0.2 in the DSS + etodolac group and 3.0+/-0.52 in the DSS-alone group, the inter-group difference being significant (p<0.01). There was no significant difference in the inflammation score between these two groups. These results showed that treatment with etodolac significantly reduced the occurrence of neoplasia, suggesting that this COX-2 inhibitor has chemopreventive activity against colitis-associated tumorigenesis.

Risk factors for advanced sporadic colorectal neoplasia in persons younger than age 50

Background: Colorectal cancer (CRC) screening is recommended for average-risk adults beginning at age 50. However, 7% of CRC occurs in persons younger than age 50, a group for which risk factors are not well defined. We sought to determine whether a retrospective case–control study could identify risk factors for sporadic CRC and advanced adenomatous polyps (together known as sporadic colorectal neoplasia [CRN]). Methods: Using the cancer registry, medical records, and endoscopy and pathology reports from six local hospitals, we identified potentially eligible persons with CRN (cases) or controls who had no neoplasia on colonoscopy between January 1, 2000 and December 31, 2002. Consenting subjects completed a survey encompassing medical and family history, physical measures, lifestyle habits, and diet. Results: Surveys were completed by 20 (15%) of 130 potentially eligible cases and by 54 (13%) of 408 potentially eligible controls. The following factors differed between cases and controls: living with a spouse/significant other (55% vs. 80%; P = 0.034); prior pelvic irradiation (20% vs. 2%; P = 0.019); having a first-degree relative with CRC (25% vs. 7%; P = 0.05); having had a prior sigmoidoscopy, colonoscopy, or barium enema (15% vs. 41%; P = 0.038); and lightest weight since age 21 (155 lbs vs. 135 lbs; gender-adjusted P = 0.049). Conclusions: The low recruitment rate of this retrospective case–control study precludes its use for a larger, more definitive study. Several potential risk factors for advanced sporadic CRN were identified. It remains to be determined whether these factors represent an artifact of selection bias or true risk factors that may be used to stratify risk and target screening in persons under age 50.

Relationship between Sporadic Hyperplastic Polyps and Colorectal Neoplasia in Hispanic Veterans

Relationship between Sporadic Hyperplastic Polyps and Colorectal Neoplasia in Hispanic Veterans

Cytokeratin 7/20 and mucin core protein expression in ulcerative colitis-associated colorectal neoplasms

Different histogenetic pathways have been suggested between ulcerative colitis (UC)-associated neoplasia and sporadic colorectal neoplasia. Little is known about the cytokeratin (CK) and mucin expression in UC-associated neoplasms. To clarify the characteristics of UC-associated colorectal carcinogenesis, we examined the immunohistochemical expression of CK7, CK20, MUC2, MUC5AC and MUC6 in 90 colorectal neoplasms, including 22 UC-associated adenocarcinomas (colitic cancer; CC), ten high-grade dysplasias (HGD) in UC, nine low-grade dysplasias (LGD) in UC, 24 sporadic tubular adenomas (TA) and 25 adenocarcinomas (AC). CK7 was positive in most of UC-associated neoplasms: 59% of CC cases, 80% of HGD and 89% of LGD, respectively, whereas, in non-UC associated neoplasia, 21% of TA and 12% of AC. The frequency of MUC6 expression in UC-associated neoplasia was 32% in CC, 30% in HGD and 44% in LGD, respectively, whereas, in non-UC associated neoplasia, 4.2% in TA and 0% in AC. MUC5AC expression in UC-associated neoplasia was detectable in 73% of CC, 90% of HGD and 89% of LGD, respectively; in non-UC associated neoplasia 67% in AC and 20% in TA. There were obvious differences in the expression of CK7 and MUC6 between UC-associated neoplasms and sporadic tumors. The incidence of MUC5AC expression in UC-associated neoplasms was also higher than sporadic tumors. These results suggest that gastric-type mucins play an important role in the initial step of CC-tumorigenesis, and CK7 and gastric-type mucins may be useful in the differential diagnosis between UC-associated neoplasms and sporadic ones.