In Infants with Neuroblastoma Standard Therapy Only Partially Reverts the Fecal Microbiome Dysbiosis Present at Diagnosis

The fecal microbiomes of 15 infants with neuroblastoma (NB) at the onset of the disease and after standard-of-care therapy have been prospectively analyzed compared to those of age-matched healthy infants. By applying several algorithms to 16S sequencing, we found that the fecal microbiomes of infants with NB at onset were abundant in <i>Pseudomonadota</i>, including different descendants of <i>Gammaproteobacteria.</i> After completing therapy, their abundance decreased to a level like that observed in healthy infants. In contrast, the <i>Bacillota</i> that showed at the onset an abundance like that of healthy infants doubled their amount after treatment. In infants with NB, the beta diversity of the fecal microbiomes was significantly reduced compared to healthy infants and patients at the end of treatment. The Random Forest algorithm and the Reingold-Tilford heat tree showed that <i>Enterobacteriaceae</i> had a higher abundance at the onset, which declined after therapy. Picrust2 inferred pathway analysis indicated that the drug treatment was associated with a reduction in the polyamine pathway, highly represented in samples of NB at the onset. In conclusion, the dysbiosis observed in infants with NB at onset changed following standard-of-care treatment. Still, the composition at the end of treatment did not completely resemble that of healthy infants.