Abstract
The human microbiome comprises a diverse set of microorganisms, which play a mostly cooperative role in processes such as metabolism and host defense. Next-generation genomic sequencing of bacterial nucleic acids now can contribute a much broader understanding of the diverse organisms composing the microbiome. Emerging evidence has suggested several roles of the microbiome in pediatric hematology/oncology, including susceptibility to infectious diseases, immune response to neoplasia, and contributions to the tumor microenvironment as well as changes to the microbiome from chemotherapy and antibiotics with unclear consequences. In this review, the authors have examined the evidence of the role of the microbiome in pediatric hematology/oncology, discussed how the microbiome may be modulated, and suggested key questions in need of further exploration.