Table 1 Effects of different bacterial species in the gut on response to CTLA-4 therapy

Bacteroides fragilis

Increased representation in feces correlates to decrease in tumor size in melanoma-bearing mice, possibly via polysaccharide A and IL-10 production.

Oral administration alone or in combination with B. cepacia to GF mice leads to decreased tumor size via DC maturation and IL-12 production

Bacteroides fragilis + Burkholderia cepacia

Oral administration in combination with B. fragilis to GF mice leads to decreased tumor size via DC maturation and IL-12 production

Bacteroides thetaiotaomicron

Oral administration alone to GF mice leads to decreased tumor size via DC maturation and IL-12 production

Faecalibacterium genus

Increased representation in the gut leads to longer progression-free and overall survival in melanoma patients due to decreased Tregs in tumor microenvironment