Importance Evidence indicates a complex link between gut microbiome, immunity, and intestinal tumorigenesis. To target the microbiota and immunity for colorectal cancer prevention and therapy, a better understanding of the relationship between microorganisms and immune cells in the tumor microenvironment is needed. Experimental evidence suggests that Fusobacterium nucleatum may promote colonic neoplasia development by down-regulating antitumor T-cell-mediated adaptive immunity. Objective To test the hypothesis that higher amount of Fusobacterium nucleatum in colorectal carcinoma tissue is associated with lower density of T-cells in tumor tissue. Design A cross-sectional analysis was conducted on colorectal carcinoma cases in two U.S. nationwide prospective cohort studies. The amount of Fusobacterium nucleatum in colorectal carcinoma tissue was measured by quantitative polymerase chain reaction assay; we equally dichotomized positive cases (high versus low). Multivariable ordinal logistic regression analysis was conducted to assess associations of the amount of Fusobacterium nucleatum with densities (quartiles) of T-cells in tumor tissue, controlling for clinical and tumor molecular features, including microsatellite instability, CpG island methylator phenotype, LINE-1 methylation, and KRAS, BRAF, and PIK3CA mutation status. We adjusted two-sided α level to 0.013 for multiple hypothesis testing. Setting The Nurses’ Health Study and the Health Professionals Follow-up Study. Participants 598 colon and rectal carcinoma cases. Main outcomes and measures Densities of CD3+, CD8+, CD45RO (PTPRC)+, and FOXP3+ T-cells in tumor tissue, determined by tissue microarray immunohistochemistry and computer-assisted image analysis. Results Fusobacterium nucleatum was detected in colorectal carcinoma tissue in 76 (13%) of 598 cases. Compared with Fusobacterium nucleatum-negative cases, Fusobacterium nucleatum-high cases were inversely associated with the density of CD3+ T-cells (for a unit increase in quartile categories of CD3+ T-cells as an outcome: multivariable odds ratio, 0.47; 95% confidence interval, 0.26 to 0.87; Ptrend = 0.006). The amount of Fusobacterium nucleatum was not significantly associated with the density of CD8+, CD45RO+, or FOXP3+ T-cells (Ptrend > 0.013). Conclusions and relevance The amount of tissue Fusobacterium nucleatum is inversely associated with CD3+ T-cell density in colorectal carcinoma tissue. Upon validation, our human population data may provide an impetus for further investigations on potential interactive roles of Fusobacterium and host immunity in carcinogenesis.

Importance Although patients with resected pancreatic adenocarcinoma are at high risk for disease recurrence, few markers are available to inform patient outcomes. Objective To evaluate alterations of the four main driver genes for pancreatic adenocarcinoma and patient outcomes after cancer resection. Design, Setting, and Participants We analyzed protein expression and DNA alterations for KRAS, CDKN2A, SMAD4, and TP53 by immunohistochemistry and next-generation sequencing in formalin-fixed, paraffin-embedded tumors from 356 patients with resected pancreatic adenocarcinoma evaluated at three U.S. centers. Associations of driver gene alterations with disease-free survival (DFS) and overall survival (OS) were evaluated using Cox proportional hazards regression with estimation of hazard ratios (HR) and 95% confidence intervals (CI) and adjustment for age, sex, tumor characteristics, institution, and peri-operative treatment. Main Outcomes DFS and OS among patients with resected pancreatic adenocarcinoma Results Patients with KRAS mutant tumors had worse DFS and OS compared to patients with KRAS wild-type tumors, with median OS of 20.3 versus 38.6 months and 5-year OS of 13.0% versus 30.2%, respectively. Particularly poor outcomes were identified in patients with KRAS G12D-mutant tumors, who had median OS of 15.3 months. Patients whose tumors lacked CDKN2A expression had worse DFS and OS compared to patients whose tumors retained CDKN2A, with median OS of 19.7 versus 24.6 months and 5-year OS of 11.9% versus 19.5%, respectively. SMAD4 status was not associated with DFS or OS, while TP53 status was associated only with DFS (P=0.04). Patients had worse DFS and OS with greater number of altered driver genes. Compared to patients with 0-2 altered genes, those with 4 altered genes had HR for DFS of 1.79 (1.24-2.59; P<0.01) and OS of 1.38 (0.98-1.94; P=0.06). Five-year OS was 18.4% for patients with 0-2 gene alterations, 14.1% for 3 alterations and 8.2% for 4 alterations. Alterations in the four driver genes were not significantly associated with local recurrence as the first site of disease recurrence. Conclusions and Relevance Patient outcomes are associated with alterations of the four main driver genes in resected pancreatic adenocarcinoma.

Nearly 10% of PDAC patients harbor germline variants, although the majority lack somatic second hits, the therapeutic significance of which warrants further study.

Background Resolvin E1 (RvE1), an endogenous lipid mediator derived from eicosapentaenoic acid (EPA), has been identified in local inflammation during the healing stage. RvE1 reduces inflammation in several types of animal models including peritonitis and retinopathy, and blocks human neutrophil transendothelial cell migration. The RvE1 receptor ChemR23 is expressed on myeloid cells such as macrophages and dendritic cells. The aim of this study was to determine whether RvE1 regulates colonic inflammation when the innate immune response of macrophages plays a key role in the pathogenesis and tissue damage. Methods/Results RvE1 receptor, ChemR23, was expressed in mouse peritoneal macrophages as defined by flow cytometry. Peritoneal macrophages were pretreated with RvE1, followed by lipopolysaccharide (LPS) stimulation whereupon of the transcriptional levels of proinflammatory cytokines were analyzed. RvE1 treatment led to the inhibition of proinflammatory cytokines including TNF-α and IL-12p40. In HEK293 cells, pretreatment with RvE1 inhibited TNF-α-induced nuclear translocation of NF-κB in a ChemR23 dependent manner. These results suggested that RvE1 could regulate pro-inflammatory responses of macrophages expressing ChemR23. Therefore, we investigated the beneficial effects of RvE1 in dextran sulfate sodium (DSS) induced colitis. RvE1 treatment led to amelioration of colonic inflammation. Conclusions These results indicate that RvE1 suppresses pro-inflammatory responses of macrophages. RvE1 and its receptor may therefore be useful as therapeutic targets in the treatment of human inflammatory bowel disease (IBD) and other inflammatory disorders.