Gut Microbiome: The Third Musketeer in the Cancer-Immune System Cross-Talk

Abstract

Abstract. The fascinating hypothesis that microbes lead to cancer has long been dwelled upon but has only been recently investigated in cancers other than those of stomach and colon. Microbes can affect cancer cells directly through toxins or metabolites. They also play a significant role in the development and maturation of the immune system and can indirectly affect cancer cells through the immune system. Reliable mouse models and affordable sequencing technologies, have made it possible in current times, to delineate the role of microbes in undermining cancer immune surveillance and indirectly promoting oncogenesis. In this review, we explore the cancer-gut microbiome-immune trialogue, focusing on pancreatic cancer. We review how gut-microbiome interacts with immune system to promote oncogenesis and how modulation of gut-microbiome can be used as an effective therapeutic strategy to reprogram the immune system for augmenting anti-tumor response and enhance immunotherapy efficacy in traditionally resistant pancreatic cancer.