The Epithelial-Stromal Microenvironment in Early Colonic Neoplasia.

Stromal cells play a central role in promoting the progression of colorectal cancer. Here, we analyze molecular changes within the epithelial and stromal compartments of dysplastic aberrant crypt foci (ACF) formed in the ascending colon, where rapidly developing interval cancers occur. We found strong activation of numerous neutrophil/monocyte chemokines, consistent with localized inflammation. The data also indicated a decrease in interferon signaling and cell-based immunity. The immune checkpoint and T-cell exhaustion gene PDCD1 was one of the most significantly upregulated genes, which was accompanied by a decrease in cytotoxic T-cell effector gene expression. In addition, CDKN2A expression was strongly upregulated in the stroma and downregulated in the epithelium, consistent with diverse changes in senescence-associated signaling on the two tissue compartments. IMPLICATIONS: Decreased CD8 T-cell infiltration within proximal colon ACF occurs within the context of a robust inflammatory response and potential stromal cell senescence, thus providing new insight into potential promotional drivers for tumors in the proximal colon.

Characterization of Mucosal Dysbiosis of Early Colonic Neoplasia.

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesions in the colon that can be detected by high-definition chromoendoscopy with contrast dye spray. Although frequently associated with synchronous adenomas, their role in colorectal tumor development, particularly in the proximal colon, is still not clear. The goal of this study was to evaluate the profile of colon-adherent bacteria associated with proximal ACF and to investigate their relationship to the presence and subtype of synchronous polyps present throughout the colon. Forty-five subjects undergoing a screening or surveillance colonoscopy were included in this retrospective study. Bacterial cells adherent to the epithelia of ACF and normal mucosal biopsies were visualized by in situ hybridization within confocal tissue sections. ACF showed significantly greater heterogeneity in their bacterial microbiome profiles compared with normal mucosa. One of the bacterial community structures we characterized was strongly correlated with the presence of synchronous polyps. Finally, using DNA mass spectrometry to evaluate a panel of colorectal cancer hotspot mutations present in the ACF, we found that three APC gene mutations were positively associated with the presence of Instestinibacter sp., whereas KRAS mutations were positively correlated with Ruminococcus gnavus. This result indicates a potential relationship between specific colon-associated bacterial species and somatically acquired CRC-related mutations. Overall, our findings suggest that perturbations to the normal adherent mucosal flora may constitute a risk factor for early neoplasia, demonstrating the potential impact of mucosal dysbiosis on the tissue microenvironment and behavior of ACF that may facilitate their progression towards more advanced forms of neoplasia.

Fecal Microbiota Transplantation for Clostridium difficile Infection: A One-Center Experience.

BACKGROUND: Clostridium difficile is a gram-positive, anaerobic, and spore-forming bacillus, which is responsible for the majority of antibiotic-associated diarrhea and colitis. OBJECTIVE: Determine if fecal microbiota transplantation (FMT) is effective in a population sample from Connecticut. METHODS: We report the clinical experience of 92 consecutive patients from one gastroenterology practice in central Connecticut treated by colonoscopy with FMT for infection with Clostridium difficile from 2012 to 2017. The analyses are based on clinical follow-up up to 3 months after the FMT procedure and on medical chart review. RESULTS: Overall, complete recovery occurred in 86% of patients. As previously reported in a limited number of previous studies, community-acquired cases were more common than hospital-acquired cases, and community-acquired cases were more likely to be female. CONCLUSIONS: Consistent with some previous reports, we found the following: the source of the donor for FMT did not make a difference in recovery: material from nonrelatives was as effective as from close relatives; and the presence of multiple comorbidities did not make a difference in recovery: patients with 2 or more comorbidities did as well as those with one or none.

Associations of dietary fat with risk of early neoplasia in the proximal colon in a population-based case-control study.

PURPOSE: Excess dietary fat consumption is strongly associated with the risk of colorectal cancer, but less is known about its role in the earliest stages of carcinogenesis, particularly within the proximal colon. In the following case-control study, we evaluated the relationship between the intake of dietary fats and the frequency of early proximal neoplasia [aberrant crypt foci (ACF) or polyps], detectable by high-definition colonoscopy with contrast dye-spray. METHODS: Average-risk screening individuals underwent a high-definition colonoscopy procedure as part of larger ongoing clinical study of precancerous lesions in the proximal colon. Dietary fat intake was assessed using the Block Brief Food Frequency Questionnaire, which estimates average dietary intake based on 70 food items. The diets of individuals with no endoscopically identifiable lesions (n = 36) were compared to those with either ACF or polyps detected in the proximal colon. RESULTS: In multivariate analysis, high dietary intake of total polyunsaturated fatty acids (PUFAs) and intake of omega-6 and omega-3 fatty acids were positively associated with neoplastic lesions in the proximal colon. When comparing ACF and polyp groups separately, a positive association was observed for both proximal polyps (OR 2.28; CI 1.16-7.09) and ACF (OR 2.86; CI 1.16-7.09) for total PUFA intake. Furthermore, the prevalence of proximal ACF was increased with higher intake of omega-6 (OR 3.54; CI 1.32-9.47) and omega-3 fatty acids (OR 2.29; CI 1.02-5.13), although there was no discernible difference in the omega-6/omega-3 ratio. CONCLUSIONS: These results suggest that dietary PUFAs may be positively associated with risk of early neoplasia in the proximal colon. This study provides further evidence that dietary PUFA composition may play an important role in altering the microenvironment within the human colon.

Endoscopic Features of Mucous Cap Polyps: A Way to Predict Serrated Polyps.

BACKGROUND/AIMS: The aims of the study were to identify whether a mucous-cap predicts the presence of serrated polyps, and to determine whether additional endoscopic findings predict the presence of a sessile serrated adenomas/polyp (SSA/P). METHODS: We analyzed 147 mucous-capped polyps with corresponding histology, during 2011-2014. Eight endoscopic features (presence of borders, elevation, rim of debris, location in the colon, size ≥10 mm, varicose vessels, nodularity, and alteration in mucosal folds) of mucous-capped polyps were examined to see if they can predict SSA/Ps. RESULTS: A total of 86% (n=126) of mucous-capped polyps were from the right sided serrated pathway (right-sided hyperplastic [n=83], SSA/Ps [n=43], traditional serrated adenoma [n=1]), 10% (n=15) were left-sided hyperplastic polyps, and 3% (n=5) were from the adenoma-carcinoma sequence. The presence of a mucous cap combined with varicose vessels was the only significant predictor for SSA/Ps. The other seven characteristics were not found to be statistically significant for SSA/Ps, although location in the colon and the presence of nodularity trended towards significance. CONCLUSIONS: Our study suggests that mucous-capped polyps have high predictability for being a part of the serrated pathway. Gastroenterologists should be alert for a mucous-capped polyp with varicose veins, as these lesions have a higher risk of SSA/P.

Proximal Aberrant Crypt Foci Associate with Synchronous Neoplasia and Are Primed for Neoplastic Progression.

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion found within the human colon. Despite their relatively high frequency in the distal colon, few studies have examined the molecular characteristics of ACF within the proximal colon. In the following study, clinical participants (n = 184) were screened for ACF using high-definition chromoendoscopy with contrast dye-spray. Following pathologic confirmation, ACF biopsies were subjected to laser capture microdissection (LCM), and epithelial cells were evaluated for somatic mutations with a customized colorectal cancer mutation panel using DNA-mass spectrometry. Samples were further characterized for microsatellite instability (MSI). Logistic models were used to associate proximal ACF with synchronous (detected during the same procedure) neoplasia. Thirty-nine percent of participants had at least one histologically confirmed proximal ACF. Individuals with a proximal ACF were significantly more likely to present with a synchronous neoplasm (P = 0.001), and specifically, a proximal, tubular, or tubulovillous adenoma (multivariable OR = 2.69; 95% confidence interval, 1.12-6.47; P = 0.027). Proximal ACF were more likely to be dysplastic (52%) compared with distal ACF (13%; P < 0.0001). Somatic mutations to APC, BRAF, KRAS, NRAS, and ERBB2 were detected in 37% of proximal ACF. Hyperplastic ACF were more often MSI-high, but there were no differences in MSI status observed by colonic location. In summary, ACF are identified in the proximal colons of approximately 40% of individuals undergoing chromoendoscopy and more often in patients with synchronous proximal adenomas.Implications: This study provides the most complete set of data, to date, that ACF represent the earliest step in the adenoma-carcinoma sequence but remain below the detection limit of conventional endoscopy.Visual Overview: http//mcr.accrjournals.org/content/molcanres/16/3/486/F1.large.jpg Mol Cancer Res; 16(3); 486-95. ©2017 AACR.

Targeted Transcriptional Profiling of Microdissected Biopsy Specimens Representing Early Colonic Neoplasia.

Our incomplete understanding of the critical changes that accompany the earliest stages of tumor initiation provides a substantial hurdle for the development of novel intervention strategies for cancer prevention. Premalignant lesions are inherently difficult to characterize given their diminutive size, creating technical obstacles for accurate genetic profiling. Here, we describe an approach combining laser-capture microdissection (LCM) with targeted RNA-sequencing to study the transcriptional state of epithelial and stromal cells during the earliest detectable stage of human colorectal neoplasia, the aberrant crypt foci (ACF). We provide a robust and reproducible workflow for RNA isolation, library preparation, and expression profiling of laser-captured cells from frozen OCT-embedded tissue specimens. It is anticipated that the methodological approach outlined in this report will provide a framework for a broad range of microgenomics analyses that can be routinely applied to many other premalignant tissues. J. Cell. Biochem. 117: 2677-2681, 2016. © 2016 Wiley Periodicals, Inc.

Distinct Transcriptional Changes and Epithelial-Stromal Interactions Are Altered in Early-Stage Colon Cancer Development.

UNLABELLED: Although the progression of mutated colonic cells is dependent upon interactions between the initiated epithelium and surrounding stroma, the nature of these interactions is poorly understood. Here, the development of an ultrasensitive laser capture microdissection (LCM)/RNA-seq approach for studying the epithelial and stromal compartments of aberrant crypt foci (ACF) is described. ACF are the earliest identifiable preneoplastic lesion found within the human colon and are detected using high-definition endoscopy with contrast dye spray. The current analysis focused on the epithelium of ACF with somatic mutations to either KRAS, BRAF, or APC, and expression patterns compared with normal mucosa from each patient. By comparing gene expression patterns among groups, an increase in a number of proinflammatory NF-κB target genes was identified that was specific to ACF epithelium, including TIMP1, RELA, and RELB Distinct transcriptional changes associated with each somatic mutation were observed and a subset of ACF display BRAF(V600E)-mediated senescence-associated transcriptome characterized by increased expression of CDKN2A Finally, LCM-captured ACF-associated stroma was found to be transcriptionally distinct from normal-appearing stroma, with an upregulation of genes related to immune cell infiltration and fibroblast activation. Immunofluorescence confirmed increased CD3(+) T cells within the stromal microenvironment of ACF and an abundance of activated fibroblasts. Collectively, these results provide new insight into the cellular interplay that occurs at the earliest stages of colonic neoplasia, highlighting the important role of NF-κB, activated stromal fibroblasts, and lymphocyte infiltration. IMPLICATIONS: Fibroblasts and immune cells in the stromal microenvironment play an important role during the earliest stages of colon carcinogenesis. Mol Cancer Res; 14(9); 795-804. ©2016 AACR.

Colorectal polyp prevention by daily aspirin use is abrogated among active smokers.

PURPOSE: Based on suggestive findings from a recent study of high-risk Japanese patients, we sought to determine whether the risk of colorectal polyps associated with smoking may be modified by daily use of aspirin in an analysis of a large US screening population. METHODS: This is a cross-sectional study of 2,918 consecutive colonoscopy patients at a university hospital over a 30-month period. Data were abstracted from electronic medical records. Multivariate models of polyp counts were used to examine the competing risks of smoking and aspirin use. Models were further stratified by polyp location (proximal vs. distal) and pathologic subtype (dysplastic vs. serrated). RESULTS: Incidental rate of polyps was higher among active smokers [incidence rate ratio (IRR) 1.72; 95 % confidence interval (CI) 1.46-2.02] and lower among daily aspirin users (IRR 0.73; 95 % CI 0.61-0.86) compared to those who used neither. Smoking interacts significantly with aspirin use resulting in loss of aspirin protection (IRR 1.69; 95 % CI 1.28-2.24). Stratified analyses demonstrate that aspirin specifically reduces the risk of traditional dysplastic adenomas (IRR 0.72; 95 % CI 0.61-0.86) not serrated/hyperplastic polyps (IRR 0.92; 95 % CI 0.72-1.17) and that the modification of aspirin protection by smoking is primarily observed within the distal colorectum (p < 0.03). CONCLUSIONS: We report for the first time, in a typical risk US clinical population, a lack of protective association of aspirin for polyps among active smokers. Future prospective studies are recommended to confirm this mitigating effect in order to improve the precision of the growing evidence base about the chemopreventive benefit of aspirin in colorectal cancer.

Presentation and Surgical Management of Duodenal Duplication in Adults.

Duodenal duplications in adults are exceedingly rare and their diagnosis remains difficult as symptoms are largely nonspecific. Clinical presentations include pancreatitis, biliary obstruction, gastrointestinal bleeding from ectopic gastric mucosa, and malignancy. A case of duodenal duplication in a 59-year-old female is presented, and her treatment course is reviewed with description of combined surgical and endoscopic approach to repair, along with a review of historic and current recommendations for management. Traditionally, gastrointestinal duplications have been treated with surgical resection; however, for duodenal duplications, the anatomic proximity to the biliopancreatic ampulla makes surgical management challenging. Recently, advances in endoscopy have improved the clinical success of cystic intraluminal duodenal duplications. Despite these advances, surgical resection is still recommended for extraluminal tubular duplications although combined techniques may be necessary for long tubular duplications. For duodenal duplications, a combined approach of partial excision combined with mucosal stripping may offer advantage.

HD chromoendoscopy coupled with DNA mass spectrometry profiling identifies somatic mutations in microdissected human proximal aberrant crypt foci.

UNLABELLED: Despite increased implementation of screening colonoscopy, interval cancers in the proximal colon remain a major public health concern. This fact underscores the limitations of current screening paradigms and the need for developing advanced endoscopic techniques. The density of aberrant crypt foci (ACF), the earliest identifiable mucosal abnormality, may serve as a surrogate marker for colon cancer risk, but has rarely been studied in the proximal colon. To this end, high-definition (HD) chromoendoscopy was conducted to define the relevance of ACF in the proximal colon. In addition, due to limited ACF size, the development of a combinatorial approach was required to maximize data acquisition obtained from individual biopsy samples. Proximal and distal ACF samples were characterized for a total of 105 mutations across 22 known tumor suppressor and proto-oncogenes using high-throughput Sequenom MassARRAY analysis. From this profiling, a discrete number of somatic mutations were identified, including APC(R876*) and FLT3(I836M), as well as a deletion within the EGFR gene. Combined, these data highlight the significance of ACF within the context of colon cancer pathogenesis, particularly in the proximal colon. IMPLICATIONS: The identification of cancer-related mutations in commonly overlooked mucosal lesions underscores the preventive benefit of implementing advanced endoscopic screening to larger patient populations, particularly in the proximal colon. Visual Overview: http://mcr.aacrjournals.org/content/early/2014/05/22/1541-7786.MCR-13-0624/F1.large.jpg. Mol Cancer Res; 12(6); 823-9. ©2014 AACR.