Gut microbes modulate host response to immune checkpoint inhibitor cancer immunotherapy

Ever since their discovery in the1670s, and proof of their link with disease in the 1870s, bacteria have had a bad name and are often called pathogens. They are regarded as the cause of diseases and things to be avoided. However, there are an estimated 100 trillion of bacteria, ten times more than the number of cells in a human body. These commensal microbes (the microbiota) live on all surface barriers of a human body and are particularly abundant and diverse in the gut. Therefore, bacteria are something that we cannot avoid.