Gut microbiota diversity and composition in predicting immunotherapy response and immunotherapy-related colitis in melanoma patients: A systematic review

Table 3 Characteristics studies exploring link between gut microbiome composition and diversity and immune-checkpoint blockade therapy-related colitis in metastatic melanoma patients treated with immune-checkpoint blockade therapy

Ref.	Year	Therapy	Method	Sample size/ timepoint	Dominant microbes	Microbial diversity
Dubin et al[33], 2015	2015	Anti-CTLA-4 immunotherapy	16S rRNA gene and shotgun metagenome sequencing of fecal samples	34	Colitis-resistant: Bacteroidetes (Bacteroidaceae, Rikenellaceae and Barnesiellaceae)	No significant difference in microbial richness and diversity
Chaput et al[27], 2017	2017	Anti-CTLA-4 immunotherapy	16S rRNA gene sequencing of fecal samples	26	Colitis-resistant: Bacteroidetes; Colitis-prone: Firmicutes	Decreased bacterial diversity was associated with colitis
Andrews et al[36], 2021		Combined ICB - Anti-PD-1 and anti-CTLA-4	16S rRNA gene and shotgun metagenome sequencing of fecal samples	38	Colitis resistant: Firmicutes; Colitis prone: Bacteriodetes	No significant difference in alpha diversity

Anti-CTLA-4: Anti-cytotoxic T lymphocyte-associated antigen-4; N/A: Not applicable; Anti-PD-1: Anti-programmed death-1; qPCR: Quantitative real-time polymerase chain reaction; ICB: Immune checkpoint blockade therapy.