Older Age at First Screening Colonoscopy is Associated With an Increased Risk of Colorectal Adenomas and Cancer.

INTRODUCTION: The goal of colorectal cancer (CRC) screening is to detect precancerous polyps before cancer development or identification of cancer at an early stage. Guidelines have recommended screening colonoscopy to start at age 45. Our aim was to determine the impact of delays in performing the first screening colonoscopy on the risk of adenoma or CRC detection. METHODS: We analyzed colonoscopy and histopathology data of average CRC risk patients who had their first screening colonoscopy between 2010 and 2017. Univariate and multivariable logistic regression was performed to determine the association between demographic variables and the risk of adenomas or CRC. RESULTS: A total of 1155 average risk patients underwent their initial screening colonoscopy during the study period. Median age was 54 years (range of 45-87) and 58.2% were females. In multivariable analysis, older age at first screening colonoscopy was significantly associated with the detection of adenomatous polyps (odds ratio 1.05, 95% confidence interval 1.04-1.07, P <0.001) and CRC (odds ratio 1.11, 95% confidence interval 1.06-1.16, P <0.001). The association between age and risk of adenomatous polyps (F-test 35.43, P =0.0019) and CRC (F-test 36.94, P =0.0017) fit an exponential growth model. It was estimated that the detection rate doubled every 14.20 years and 4.75 years for adenomas and CRC, respectively. CONCLUSION: We found that older age at the initial performance of a screening colonoscopy was associated with increased detection of adenomatous polyps and CRC. This work highlights the need for guideline adherence for the prevention of CRC development.

Double pigtail stent placement as an adjunct to lumen-apposing metal stentsfor drainage of pancreatic fluid collections may not affect outcomes: A multicenter experience.

BACKGROUND AND OBJECTIVES: EUS-guided drainage of pancreatic fluid collections (PFCs) has been increasingly performed using lumen-apposing metal stents (LAMS). However, recent data have suggested higher adverse event rates with LAMS compared to double pigtail plastic stents (DPS) alone. To decrease risks, there has been anecdotal use of placing DPS through the LAMS. We aimed to determine whether the placement of DPS through cautery-enhanced LAMS at time of initial placement decreases adverse events or need for reintervention. METHODS: We performed a multicenter retrospective study between January 2015 and October 2017 examining patients who underwent EUS-guided drainage of pseudocysts (PP), walled-off necrosis (WON), and postsurgical fluid collection using a cautery enhanced LAMS with and without DPS. RESULTS: There were 68 patients identified at 3 US tertiary referral centers: 44 PP (65%), 17 WON (25%), and 7 PFSC (10%). There were 35 patients with DPS placed through LAMS (Group 1) and 33 with LAMS alone (Group 2). Overall technical success was 100%, clinical success was 94%, and adverse events (bleeding, perforation, stent occlusion, and stent migration) occurred in 28% of patients. Subgroup analysis compared specific types of PFCs and occurrence of adverse events between each group with no significant difference detected in adverse event or reintervention rates. CONCLUSION: This multicenter study of various types of PFCs requiring EUS-guided drainage demonstrates that deployment of DPS across cautery-enhanced LAMS at the time of initial drainage does not have a significant effect on clinical outcomes, adverse events, or need for reinterventions.

Risk of Colorectal Cancer in Serrated Polyposis Syndrome: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Serrated polyposis syndrome (SPS) is characterized by development of numerous serrated lesions throughout the colorectum and increased risk of colorectal cancer (CRC). However, SPS has been an underrecognized CRC predisposition syndrome, and the true risk of CRC in SPS, both overall and in surveillance, is not known. The aim of this systematic review and meta-analysis is to describe the risk of CRC in patients with SPS. METHODS: Electronic databases were searched on March 25, 2021, for studies describing CRC risk in SPS. Random-effects meta-analysis was performed to assess pooled risk of CRC among SPS patients. Primary outcomes were risk of CRC at time of SPS diagnosis and during surveillance following diagnosis of SPS. Secondary outcomes included risk of CRC prior to diagnosis of SPS and effect of World Health Organization subtype on CRC risk. RESULTS: Thirty-six studies including 2788 patients with SPS were included in the analysis. Overall risk of CRC in SPS was 19.9% (95% confidence interval [CI], 15.3%-24.5%). CRC risk at the time of diagnosis was 14.7% (95% CI, 11.4%-18.8%), while risk during surveillance was 2.8% (95% CI, 1.8%-4.4%), or 7 cases per 1000 person-years. SPS patients also had a high incidence of history of CRC prior to SPS diagnosis (7.0%; 95% CI, 4.6%-11.7). Subgroup analysis did not reveal any significant differences based on World Health Organization subtype. CONCLUSIONS: Our meta-analysis demonstrated that patients with SPS have an elevated risk of CRC, which is highest at the time of diagnosis and suggests the importance of early SPS recognition and screening to modify CRC risk. The persistently elevated CRC risk during surveillance supports current guidelines recommending heightened surveillance protocols.

Posterior Reversible Encephalopathy Syndrome Presenting Atypically as a Non-Convulsive Seizure.

BACKGROUND Posterior reversible encephalopathy syndrome (PRES), also known as reversible posterior leukoencephalopathy, is a neurotoxic state with multiple etiologies characterized by altered mental state, headaches, visual abnormalities, and seizures. This clinico-radiological syndrome is rare, and a high index of suspicion is needed to diagnose, provide adequate treatment, and prevent irreversible neurological sequelae. CASE REPORT We present a case of a woman with end-stage renal disease (ESRD) who presented with acute confusion and non-convulsive seizures and was later diagnosed with PRES. In this case, altered mental status was initially thought to be secondary to uremic encephalopathy. A diagnosis of PRES was subsequently made after she had several sessions of HD without significant improvement in her mental state, prompting magnetic resonant imaging (MRI) for further evaluation. Specific risk factors for PRES, including blood pressure fluctuations, were targeted and she made significant clinical recovery but had residual functional impairment. CONCLUSIONS This case underscores the need for a high index of suspicion, especially in cases with atypical presentation, as delayed diagnosis can lead to suboptimal outcomes.

Bioengineering for curcumin loaded carboxymethyl guargum/reduced graphene oxide nanocomposites for chronic wound healing applications.

Biomimetic scaffolds engineering for improved collagen, epithelial cutaneous and fibrous tissue regeneration remains challenging for wound healing. To address these issues, this study aimed to report on the fabrication and characterization of electrospun of carboxymethyl guargum (CMGG), reduced graphene oxide (rGO) nanocomposite dressings loaded with curcumin for chronic wound healing applications. SEM and XRD examined the morphology of nanofibers and resulted in excellent porosity. TGA and FT-IR were done, which revealed the nanofibers' thermal and chemical interactions. CMGG, rGO nanocomposite with curcumin was investigated for in-vitro wound healing assay by scratch wound healing model using 3T3 L1 fibroblast cell lines and conducted in vitro drug-releasing studies. These nanocomposites showed 100% wound closure by the proliferation of fibroblast cell lines 3T3-L1 within 48 h and showed controlled drug release. Further, in vivo results also showed that the CMGG, rGO nanocomposite with curcumin has the potential wound healing effects. Histological studies showed that the CMGG, rGO nanocomposite with curcumin has the potential for wound healing, which indicates that the biomimetic CMGG nanofibers have an excellent healing effect on chronic wounds.

The Correlation between Vitamin D Levels and the Risk of Postoperative Recurrence in Crohn's Disease.

BACKGROUND AND AIMS: Vitamin D deficiency has been associated with disease activity in Crohn's disease (CD). We assessed whether there is a correlation between vitamin D levels and the risk of postoperative recurrence in CD. METHODS: CD patients who underwent surgery were identified from a prospectively maintained database at the University of Chicago. The primary endpoint was the correlation of serum 25-hydroxy vitamin D levels measured at 6-12 months after surgery and the proportion of patients in endoscopic remission, defined as a simple endoscopic score for CD of 0. Clinical, biological (C-reactive protein), and histologic recurrences were also studied. RESULTS: Among a total of 89 patients, 17, 46, and 26 patients had vitamin D levels of <15, 15-30, and >30 ng/mL, respectively. Patients with higher vitamin D levels were significantly more likely to be in endoscopic remission compared to those with lower levels (23, 42, and 67% in ascending tertile order; p = 0.028). On multivariate analysis, vitamin D >30 ng/mL (odds ratio [OR] 0.22, 95% confidence interval [CI] 0.07-0.66, p = 0.006) and anti-tumor necrosis factor agent treatment (OR 0.25, 95% CI 0.08-0.83, p = 0.01) were associated with reduced risk of endoscopic recurrence. Rates of clinical, biological, and histologic remission trended to be higher in patients with higher vitamin D levels (p = 0.17, 0.55, 0.062, respectively). CONCLUSION: In the present study, higher vitamin D level was associated with lower risk of postoperative endoscopic CD recurrence. Further, studies are warranted to assess the role of vitamin D in postoperative CD recurrence.

Effective Treatment of Acute Severe Ulcerative Colitis in Pregnancy Is Associated With Good Maternal and Fetal Outcomes.

Data regarding the management and outcomes of acute severe ulcerative colitis (ASUC) in pregnant patients is sparse, consisting mainly of case reports.1-3 We report on the largest cohort of pregnant patients hospitalized with ASUC and performed a systematic review of the medical literature.

Population Difference in Allele Frequency of HLA-C*05 and Its Correlation with COVID-19 Mortality.

BACKGROUND: coronavirus disease 2019 (COVID-19) causes severe illness including cytokine storms, but mortality among countries differs largely. In the present study, we investigated the association between human leukocyte antigen (HLA) class I, which plays a major role in susceptibility to viral infections, and the mortality of COVID-19. METHODS: data of allele frequencies of HLA-A, -B and -C and COVID-19 mortality were obtained for 74 countries from the Allele Frequency Net Database and worldometer.info. Association between allele frequency of each HLA and mortality was assessed by linear regression followed by multivariable regression. Subsequently, association of HLA-C*05 to its receptor KIR2DS4fl, expressed on natural killer (NK) cells, and differential mortality to historic pandemics were analyzed. RESULTS: HLA-A*01, -B*07, -B*08, -B*44 and -C*05 were significantly associated with the risk of deaths (adjusted p = 0.040, 0.00081, 0.047, 0.0022, 0.00032, respectively), but only HLA-C*05 remained statistically significant (p = 0.000027) after multivariable regression. A 1% increase in the allele frequency of HLA-C*05 was associated with an increase of 44 deaths/million. Countries with different mortality could be categorized by the distribution of HLA-C*05 and its receptor KIR2DS4fl, which in combination cause NK cell-induced hyperactive immune response. Countries with similar ethnic and/or geographic background responded in a similar pattern to each pandemic. CONCLUSIONS: we demonstrated that allele frequency of HLA-C*05 and the distribution pattern with its receptor KIR2DS4fl strongly correlated with COVID-19 mortality. Host genetic variance of innate immunity may contribute to the difference in mortality among various countries and further investigation using patient samples is warranted.

Systemic review and network meta-analysis: Prophylactic antibiotic therapy for spontaneous bacterial peritonitis.

BACKGROUND: Spontaneous bacterial peritonitis (SBP) is an important prognostic factor for outcomes in patients with cirrhosis. Antibiotic prophylaxis is recommended in patients at high risk for developing SBP, but the choice of antibiotics remains unclear. AIM: To evaluate the efficacy of various antibiotics for prophylaxis of SBP based on randomized control trials (RCTs). METHODS: Electronic databases were searched through November 2018 for RCTs evaluating the efficacy of therapies for primary or secondary prophylaxis of SBP. The primary outcome was the development of SBP. Sensitivity analyses limited to studies of primary or secondary prophylaxis and studies reported after 2010 were performed. The secondary outcome was the risk of all-cause mortality or transplant. The outcomes were assessed by rank of therapies based on network meta-analyses. Individual meta-analyses were also performed. RESULTS: Thirteen RCTs (1742 patients) including norfloxacin, ciprofloxacin, rifaximin, trimethoprim-sulfamethoxazole (TMP-SMX), or placebo/no comparator were identified. Individual meta-analyses showed superiority of rifaximin over norfloxacin as well as norfloxacin and TMP-SMX over placebo. Network meta-analysis demonstrated the rank of efficacy in reducing the risk of SBP as: Rifaximin, ciprofloxacin, TMP-SMX, norfloxacin, and placebo/no comparator. Rifaximin ranked highest in sensitivity analyses limited to studies of primary or secondary prophylaxis and studies reported after 2010. Similarly, rifaximin ranked highest in reducing the risk of death/transplant. CONCLUSION: The present comprehensive network meta-analysis provides RCT based evidence for superior efficacy of rifaximin compared to other antibiotics for the prophylaxis of SBP and reducing risk of death/transplant. Further RCTs are warranted to confirm our findings.

Efficacy of various endoscopic modalities in detecting dysplasia in ulcerative colitis: A systematic review and network meta-analysis.

BACKGROUND: Longstanding ulcerative colitis (UC) is associated with an increased risk of colonic neoplasia. Various endoscopic modalities, such as chromoendoscopy (CE), narrow band imaging (NBI) and random biopsy have been introduced for surveillance, however, there exists a paucity of direct comparisons between them. We aimed to conduct a network meta-analysis of randomized controlled trials (RCTs) performed for surveillance of neoplasia in UC. AIM: To provide a comparative evaluation of the efficacy of the above-mentioned various modalities. METHODS: We searched MEDLINE/PubMed, Web of Science, Embase, Google Scholar and Cochrane Central Registry through May 2016 for RCTs evaluating the efficacy of endoscopic modalities for surveillance of neoplasia in UC. The primary outcomes of interest were dysplasia (low- or high-grade) detection rates per biopsy and per patient, and dysplasia numbers per patient. Studies were simultaneously analyzed using a random-effects network meta-analysis under the Bayesian framework to identify the modality with the highest dysplasia detection rate. The best ranking probability for the dysplasia detection rate was analyzed by surface under the cumulative ranking (SUCRA) technique. RESULTS: Six prospective RCTs of a total 1038 patients were identified. We identified 4 different modalities; white light (WL) high definition (HD) or standard definition (SD), CE HD, and NBI HD. For dysplasia per biopsy, direct meta-analysis showed superiority of NBI HD over WL HD and CE HD over WL SD. Network meta-analysis demonstrated the rank order of best modality as NBI HD, CE HD, WL HD and WL SD with close SUCRA scores of the first two. For dysplasia per patient, direct meta-analyses showed equivocal results between each modality. Network meta-analysis demonstrated the rank order of best modality as WL HD, NBI HD, CE HD and WL SD with small differences of the SUCRA score among the first two. For dysplasia numbers per patient, direct meta-analysis showed superiority of CE HD over WL SD. Network meta-analysis demonstrated the rank order of best modality as WL HD, NBI HD, CE HD, and WL SD with small differences of the SUCRA score among the first three. CONCLUSION: We demonstrated that there were small differences among WL HD, NBI HD, and CE HD, while WL SD was inferior, in detecting dysplasia in UC.

Losartan and Vitamin D Inhibit Colonic Tumor Development in a Conditional Apc-Deleted Mouse Model of Sporadic Colon Cancer.

Colorectal cancer is a leading cause of cancer deaths. The renin-angiotensin system (RAS) is upregulated in colorectal cancer, and epidemiologic studies suggest RAS inhibitors reduce cancer risk. Because vitamin D (VD) receptor negatively regulates renin, we examined anticancer efficacy of VD and losartan (L), an angiotensin receptor blocker. Control Apc+/LoxP mice and tumor-forming Apc+/LoxP Cdx2P-Cre mice were randomized to unsupplemented Western diet (UN), or diets supplemented with VD, L, or VD+L, the latter to assess additive or synergistic effects. At 6 months, mice were killed. Plasma Ca2+, 25(OH)D3, 1α, 25(OH)2D3, renin, and angiotensin II (Ang II) were quantified. Colonic transcripts were assessed by qPCR and proteins by immunostaining and blotting. Cancer incidence and tumor burden were significantly lower in Cre+ VD and Cre+ L, but not in the Cre+ VD+L group. In Apc+/LoxP mice, VD increased plasma 1,25(OH)2D3 and colonic VDR. In Apc+/LoxP-Cdx2P-Cre mice, plasma renin and Ang II, and colonic tumor AT1, AT2, and Cyp27B1 were increased and VDR downregulated. L increased, whereas VD decreased plasma renin and Ang II in Cre+ mice. VD or L inhibited tumor development, while exerting differential effects on plasma VD metabolites and RAS components. We speculate that AT1 is critical for tumor development, whereas RAS suppression plays a key role in VD chemoprevention. When combined with L, VD no longer increases active VD and colonic VDR in Cre- mice nor suppresses renin and Ang II in Cre+ mice, likely contributing to lack of chemopreventive efficacy of the combination.

IBD-associated Colon Cancers Differ in DNA Methylation and Gene Expression Profiles Compared With Sporadic Colon Cancers.

BACKGROUND AND AIMS: As ulcerative colitis [UC]-associated colorectal cancer [CRC] and sporadic CRC differ in presentation and molecular features, we sought to evaluate differences in the impact of DNA methylation on gene expression. METHODS: DNA methylation was assessed in 11 UC-CRCs and adjacent tissue and 11 sporadic CRCs and adjacent tissue, using Illumina arrays. RNA sequencing was performed on 10 UC-CRCs and adjacent tissue and eight sporadic CRCs and adjacent tissues. Differences in DNA methylation and transcript expression, as well as their correlation in the same tissues, were assessed. Immunohistochemistry was performed for three proteins, ANPEP, FAM92A1, and STK31, all of which exhibited an inverse correlation between DNA methylation and transcript expression in UC. RESULTS: Thirty three loci demonstrated differences in DNA methylation between UC-CRC and adjacent tissue. In contrast, there were 4204 differentially methylated loci between sporadic colon cancer and adjacent tissue. Eight hundred eighty six genes as well as 10 long non-coding RNAs [lncRNA] were differentially expressed between UC-CRC and adjacent tissues. Although there were no differentially methylated loci between UC and sporadic CRC, 997 genes and 38 lncRNAs were differentially expressed between UC-CRC and sporadic CRC. In UC, 18 genes demonstrated a negative correlation between DNA methylation and transcript expression. Evaluation of protein expression related to three genes, ANPEP, FAM92A1, and STK31, confirmed down-regulation of ANPEP and up-regulation of STK31 in UC-CRC. CONCLUSIONS: Regulation of transcript expression by DNA methylation involves genes key to colon carcinogenesis and may account for differences in presentation and outcomes between inflammatory bowel disease and sporadic colon cancer.

A comparison of the risk of postoperative recurrence between African-American and Caucasian patients with Crohn's disease.

BACKGROUND: Many patients with Crohn's disease will develop complications that require surgery. Recurrence after surgery is common. AIM: To assess racial differences in postoperative recurrence between African-Americans and Caucasians. METHODS: Medical records of Crohn's disease patients who underwent surgery (ileal, colonic, or ileocolonic resection) between June 2014 and June 2016 were reviewed. The primary endpoints were clinical and endoscopic remission at 6-12 months after a Crohn's disease surgery. Secondary outcomes included biological and histologic remission. Risks of recurrence were assessed by univariate, multivariate, and propensity score-matched analysis. RESULTS: Thirty-six African-American and 167 Caucasian patients with Crohn's disease were included for analysis. There was no difference in disease location, disease behaviour, type of surgery performed, and pre- or postoperative medication use between the two groups. The rate of endoscopic remission did not differ between African-American and Caucasian patients (50% vs 42%, P = 0.76), and race did not influence the risk of endoscopic recurrence on univariate, multivariate, or propensity score-matched analysis. The rate of clinical remission was significantly lower in African-American patients compared to Caucasian patients (36% vs. 63%, P = 0.008). African-American race was significantly associated with clinical recurrence on univariate (odds ratio (OR) 6.76, 95% CI 1.50-30.40; P = 0.01), multivariate (OR 5.02, 95% CI 1.60-15.80; P = 0.006), and propensity-matched analysis (68% vs. 32% in Caucasians, P = 0.005). Rates of biologic and histologic remission were similar between the two groups on all analyses. CONCLUSIONS: We found that African-American patients with Crohn's disease have a similar degree of objective measures of mucosal inflammation after surgery including endoscopic recurrence as compared to Caucasian patients. However, African-American race was significantly associated with clinical recurrence, suggesting the presence of ethnic variation in postoperative presentation in Crohn's disease.

Increased mucosal expression of miR-215 precedes the development of neoplasia in patients with long-standing ulcerative colitis.

Identification of biological markers predicting the onset of neoplasia in patients with long-standing ulcerative colitis (UC) could allow for risk stratification in this population. In this study, we retrospectively identified subjects with chronic UC who developed colon neoplasia (n = 16) matched to UC patients who never developed neoplasia. RNA was extracted from archived colonic biopsies obtained at an interval of 1-2 years prior and 3-5 years prior to the onset of neoplasia. miRNA expression was assessed using Nanostring arrays in 12 subjects, and significantly up-regulated miRNAs were evaluated by real time pcr in the entire cohort of patients. Expression of miR-215 was also assessed in UC-associated colon cancers and compared to p53 expression. By array analysis, there were 17 significantly down-regulated and 7 significantly up-regulated miRNAs in subjects who later developed neoplasia. miR-215 was significantly up-regulated both 1-2 years prior to the onset of neoplasia (3.5-fold, p < 0.001) and 3-5 years prior to the onset of neoplasia (5.4-fold, p = 0.007). miR-215 expression was also increased in UC-associated colon cancers (5.3-fold, p = 0.03) and adjacent non-dysplastic UC tissue (6.2-fold, p = 0.02). p53 was expressed in 20% of patients prior to the onset of neoplasia and in 67% of UC-associated colon cancers, although was not correlated with miR-215 expression. Our data demonstrates that expression of miR-215 can discriminate patients who progressed to neoplasia from non-progressors as early as 5 years prior to the diagnosis of neoplasia, supporting that this and perhaps other miRNAs could serve as predictive biomarkers to risk stratify patients with chronic UC.

miR-193a-3p is a Key Tumor Suppressor in Ulcerative Colitis-Associated Colon Cancer and Promotes Carcinogenesis through Upregulation of IL17RD.

Purpose: Patients with ulcerative colitis are at increased risk for colorectal cancer, although mechanisms underlying neoplastic transformation are poorly understood. We sought to evaluate the role of microRNAs in neoplasia development in this high-risk population.Experimental Design: Tissue from 12 controls, 9 ulcerative colitis patients without neoplasia, and 11 ulcerative colitis patients with neoplasia was analyzed. miRNA array analysis was performed and select miRNAs assayed by real-time PCR on the discovery cohort and a validation cohort. DNA methylation of miR-193a was assessed. Following transfection of miR-193a-3p, proliferation, IL17RD expression, and luciferase activity of the 3'UTR of IL17RD were measured. Tumor growth in xenografts as well as EGFR signaling were assessed in HCT116 cells expressing IL17RD with either a mutant 3' untranslated region (UTR) or wild-type (WT) 3'UTR.Results: miR-31, miR-34a, miR-106b, and miR-193a-3p were significantly dysregulated in ulcerative colitis-neoplasia and adjacent tissue. Significant down-regulation of miR-193a-3p was also seen in an independent cohort of ulcerative colitis cancers. Changes in methylation of miR-193a or expression of pri-miR-193a were not observed in ulcerative colitis cancer. Transfection of miR-193a-3p resulted in decreased proliferation, and identified IL17RD as a direct target of miR-193a-3p. IL17RD expression was increased in ulcerative colitis cancers, and miR-193a-3p treatment decreased growth and EGFR signaling of HCT116 cells in xenografts expressing both IL17RD with WT 3'UTR compared with cells expressing IL17RD with mutant 3'UTR.Conclusions: miR-193a-3p is downregulated in ulcerative colitis neoplasia, and its loss promotes carcinogenesis through upregulation of IL17RD. These findings provide novel insight into inflammation-driven colorectal cancer and could suggest new therapeutic targets in this high-risk population. Clin Cancer Res; 23(17); 5281-91. ©2017 AACR.

ADAM17 is a Tumor Promoter and Therapeutic Target in Western Diet-associated Colon Cancer.

PURPOSE: Epidermal growth factor receptors (EGFR) are required for tumor promotion by Western diet. The metalloprotease, ADAM17 activates EGFR by releasing pro-EGFR ligands. ADAM17 is regulated by G-protein-coupled receptors, including CXCR4. Here we investigated CXCR4-ADAM17 crosstalk and examined the role of ADAM17 in tumorigenesis. EXPERIMENTAL DESIGN: We used CXCR4 inhibitor, AMD3100 and ADAM17 inhibitor, BMS566394 to assess CXCR4-ADAM17 crosstalk in colon cancer cells. We compared the expression of CXCR4 ligand, CXCL2, and ADAM17 in mice fed Western diet versus standard diet. Separately, mice were treated with marimastat, a broad-spectrum ADAM17 inhibitor, or AMD3100 to assess EGFR activation by ADAM17 and CXCR4. Using Apc-mutant Min mice, we investigated the effects of ADAM17/10 inhibitor INCB3619 on tumorigenesis. To assess the effects of colonocyte ADAM17, mice with ADAM17 conditional deletion were treated with azoxymethane (AOM). ADAM17 expression was also compared in colonocytes from primary human colon cancers and adjacent mucosa. RESULTS: CXCL12 treatment activated colon cancer cell EGFR signals, and CXCR4 or ADAM17 blockade reduced this activation. In vivo, Western diet increased CXCL12 in stromal cells and TGFα in colonocytes. Marimastat or AMD3100 caused >50% reduction in EGFR signals (P < 0.05). In Min mice, INCB3619 reduced EGFR signals in adenomas and inhibited intestinal tumor multiplicity (P < 0.05). In the AOM model, colonocyte ADAM17 deletion reduced EGFR signals and colonic tumor development (P < 0.05). Finally, ADAM17 was upregulated >2.5-fold in human malignant colonocytes. CONCLUSIONS: ADAM17 is a Western diet-inducible enzyme activated by CXCL12-CXCR4 signaling, suggesting the pathway: Western diet→CXCL12→CXCR4→ADAM17→TGFα→EGFR. ADAM17 might serve as a druggable target in chemoprevention strategies. Clin Cancer Res; 23(2); 549-61. ©2016 AACR.