Significance We demonstrate, to our knowledge for the first time, that bacterial biofilms are associated with colorectal cancers, one of the leading malignancies in the United States and abroad. Colon biofilms, dense communities of bacteria encased in a likely complex matrix that contact the colon epithelial cells, are nearly universal on right colon tumors. Most remarkably, biofilm presence correlates with bacterial tissue invasion and changes in tissue biology with enhanced cellular proliferation, a basic feature of oncogenic transformation occurring even in colons without evidence of cancer. Microbiome profiling revealed that biofilm communities on paired normal mucosa cluster with tumor microbiomes but lack distinct taxa differences. This work introduces a previously unidentified concept whereby microbial community structural organization exhibits the potential to contribute to disease progression.

Summary IL-17-producing Th17 cells, generated through a STAT3-dependent mechanism, have been shown to promote carcinogenesis in many systems, including microbe-driven colon cancer. Additional sources of IL-17, such as γδ T cells, become available under inflammatory conditions, but their contributions to cancer development are unclear. In this study, we modeled Th17-driven colon tumorigenesis by colonizing MinApc+/- mice with the human gut bacterium, enterotoxigenic Bacteroides fragilis (ETBF), to investigate the link between inflammation and colorectal cancer. We found that ablating Th17 cells by knocking out Stat3 in CD4+ T cells delayed tumorigenesis, but failed to suppress the eventual formation of colonic tumors. However, IL-17 blockade significantly attenuated tumor formation, indicating a critical requirement for IL-17 in tumorigenesis, but from a source other than Th17 cells. Notably, genetic ablation of γδ T cells in ETBF-colonized Th17-deficient Min mice prevented the late emergence of colonic tumors. Taken together, these findings support a redundant role for adaptive Th17 cell- and innate γδT17 cell-derived IL-17 in bacteria-induced colon carcinogenesis, stressing the importance of therapeutically targeting the cytokine itself rather than its cellular sources.

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We describe extremely rare cases of vocal cord palsy following surgical insertion of a chemo port. Our cohort consisted of patients with cancer who developed hoarseness immediately after central venous line placement for the administration of chemotherapy, with vocal cord palsy confirmed with flexible laryngoscopy. Given the timing, central venous line placement appears to be the most likely cause.