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IBCN 2017: Keynote Lecture - The Microbiota: A New Variable Impacting Cancer Immunotherapy Outcomes

Lisbon, Portugal (UroToday.com) Tom Gajewski from The University of Chicago, Chicago, IL discussed ‘The Microbiota: A New Variable Impacting Cancer Immunotherapy Outcomes’. The working model is immunobiology of T cell inflamed versus no-inflamed tumor microenvironment. Presence of Tregs and expression of PDL1 and IDO are associated with a CD8+ T cell infiltrate. The frequency of the T-cell inflamed gene signature across solid tumors including bladder cancer of The Cancer Genome Atlas. Current molecular mechanisms that explain the T cell inflamed versus no-inflamed tumor microenvironment include somatic differences at the level of tumor cells, germline genetic differences at the level of the host and environment differences in microbiota as well as immunologic/pathogen exposure history of the patients.

Microbiota shape systemic immunity is being explored regarding anti-tumor immunity with preliminary data in mice showing microbiota have anti-tumor activity and response to anti-PDL1. Taking these data assessing response to therapy and PDL1 expression showed similar findings in humans. Fecal transfer into germ-free mice mediated slow and fast tumor growth which correlated with tumor response of the human host. The T cell inflamed tumor microenvironment may serve as a predictive biomarker for response to immunotherapies. Mechanisms and further research will elucidate these findings.

Speaker(s): Tom Gajewski, The University of Chicago, Chicago, IL

Written by: Stephen B. Williams, M.D., Associate Professor, Division of Urology, The University of Texas Medical Branch, Galveston, TX. and Ashish M. Kamat, M.D. Professor, Department of Urology, Division of Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX., at the International Bladder Cancer Network - October 21, 2017- Lisbon, Portugal