Recent insights into the role of the microbiome in malignant and benign hematologic diseases

• Microbiota includes commensal and pathogenic microorganisms colonizing human body. Dysbiosis may favour the development of oncologic benign hematologic diseases. Chemotherapy immunesuppression worsen dysbiosis infections. Antibiotic prophylaxis/therapy be detrimental for microbiome composition. Novel target therapies induce possibly impacting on outcome. Growing evidence suggests impact alteration, named dysbiosis, neoplasms, infections, inflammatory diseases, immuno-mediated disorders. Regarding most data regard hematopoietic stem cell transplant (HSCT). In this review, we systematically evaluate studies concerning in malignant disorders beyond HSCT. A permissive microbiota is associated to malignancies (including acute leukemia, lymphoma, multiple myeloma), as well iron deficiency anemia, autoimmune cytopenias, aplastic anemia. This happens through various mechanisms; chronic triggering, epithelial barrier antigen dissequestration, molecular mimicry. Hematologic (chemo immunosuppression) induce/worsen disease progression infectious complications. Antibiotics also with possible long-term consequences. Finally, novel are likely alter microbiome, inducing gut inflammation (i.e. small molecules such tyrosine-kinase-inhibitors) or enhancing host’s immune system (as observed CAR-T cells checkpoint inhibitors).