Microbiome and Cancer: Examining the Influence of Gut Microbiota on Immunotherapy Efficacy and Toxicity

The gut microbiome is a complex ecosystem of trillions of microorganisms that are essential to help regulate the human immune system and its role in cancer treatment outcomes has been identified as particularly relevant for immunotherapy. The number of cancers such as melanoma, lung or renal cancer has dramatically changed since Immune Checkpoint Inhibitors (ICIs) including anti-PD-1, anti-PD-L1 and anti CTLA-4 therapies developed. However, response rates are limited and challenges remain regarding immune-related adverse events (irAEs). Recent studies have firmly shown ICIs efficacy and toxicity to be influenced by the composition of an individual’s gut microbiota. Several bacterial taxa, including Akkermansia muciniphila, Faecalibacterium and Bifidobacterium are associated with better response to therapy whereas dysbiosis can contribute both treatment failure and irAEs. It examines the mechanisms of gut microbiota in affecting immune responses and discusses the way of translating these findings might be used to improve immunotherapy, as well describing potential actions already available (probiotic or pre/pro-symbiotics or Fecal Microbiota Transplantation (FMT)) for improving efficacy, it also presents implications on clinical perspectives using microbiome-based strategies determining specific cancer care [1]. Understanding the important role of gut-cancer immune axis in cancer immunotherapy, a more complete understanding on its mechanisms could lead to new possibilities for improving patient outcomes and reducing toxicity.