It has been widely established that the gut microbiota influences numerous and diverse physiological functions, hence has a prevalent role in human health. Not only by providing nutrients and vitamins but also by preservation of epithelial mucosa homeostasis and by supporting the innate and adaptive immunity.
Recently, it has become more and more elucidated that the interplay of the gut microbiota with the immune system has a significant impact on the patient’s health. This complex interaction between the gut microbiota and our immune system has evolved as a means to maintain a symbiotic relationship. When operating optimally, this symbiosis ensures a protective response against pathogens and the maintenance of regulatory pathways involved in the immune tolerance to innocuous antigens.
It is now becoming increasingly apparent that the microbiome can also influence the development of cancer and impact the outcome of cancer treatment. Therefore, integrating gut microbiome effects with other tumour and host factors, regulating immunotherapy responsiveness versus resistance, could facilitate optimisation of therapeutic outcomes of cancer patients.