Association of Fusobacterium species in pancreatic cancer tissues with molecular features and prognosis

Recently, bacterial infection causing periodontal disease has attracted considerable attention as a risk factor for pancreatic cancer. Fusobacterium species is an oral bacterial group of the human microbiome. Some evidence suggests that Fusobacterium species promote colorectal cancer development; however, no previous studies have reported the association between Fusobacterium species and pancreatic cancer. Therefore, we examined whether Fusobacterium species exist in pancreatic cancer tissue. Using a database of 283 patients with pancreatic ductal adenocarcinoma (PDAC), we tested cancer tissue specimens for Fusobacterium species. We also tested the specimens for KRAS, NRAS, BRAF and PIK3CA mutations and measured microRNA-21 and microRNA-31. In addition, we assessed epigenetic alterations, including CpG island methylator phenotype (CIMP). Our data showed an 8.8% detection rate of Fusobacterium species in pancreatic cancers; however, tumor Fusobacterium status was not associated with any clinical and molecular features. In contrast, in multivariate Cox regression analysis, compared with the Fusobacterium species-negative group, we observed significantly higher cancer-specific mortality rates in the positive group (p = 0.023). In conclusion, Fusobacterium species were detected in pancreatic cancer tissue. Tumor Fusobacterium species status is independently associated with a worse prognosis of pancreatic cancer, suggesting that Fusobacterium species may be a prognostic biomarker of pancreatic cancer

Marine ω-3 polyunsaturated fatty acids and risk for colorectal cancer according to microsatellite instability

© 2015 The Author. Published by Oxford University Press. All rights reserved. Background: Chronic inflammation is involved in the development of colorectal cancer (CRC) and microsatellite instability (MSI), a distinct phenotype of CRC. Experimental evidence indicates an anti-inflammatory and antineoplastic effect of marine ω-3 polyunsaturated fatty acids (PUFAs). However, epidemiologic data remain inconclusive. Methods: We investigated whether the association between marine ω-3 PUFAs and CRC varies by MSI-defined subtypes of tumors in the Nurses\u27 Health Study and Health Professionals Follow-up Study. We documented and classified 1125 CRC cases into either MSI-high tumors, in which 30% or more of the 10 microsatellite markers demonstrated instability, or microsatellite-stable (MSS) tumors. Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of MSS tumors and MSI-high tumors in relation to marine ω-3 PUFA intake. All statistical tests were two-sided. Results: Marine ω-3 PUFA intake was not associated with overall incidence of CRC. However, a statistically significant difference was detected by MSI status (P heterogeneity =. 02): High marine ω-3 PUFA intake was associated with a lower risk for MSI-high tumors (comparing 0.30g/d with \u3c0.10g/d: multivariable HR = 0.54, 95% CI = 0.35 to 0.83, P linearity =. 03) but not MSS tumors (HR = 0.97, 95% CI = 0.78 to 1.20, P linearity =. 28). This differential association appeared to be independent of CpG island methylator phenotype and BRAF mutation status. Conclusions: High marine ω-3 PUFA intake is associated with lower risk for MSI-high CRC but not MSS tumors, suggesting a potential role of ω-3 PUFAs in protection against CRC through DNA mismatch repair. Further research is needed to confirm our findings and elucidate potential underlying mechanisms