Depletion of Faecalibacterium prausnitzii in the gut microbiota of children diagnosed with cancer

Abstract Background: A beneficial composition of the microbiome is essential for maintaining human health and to protect the body against pathogens. The identification of microbes with oncogenic potential suggests a possible link between changes in the gastrointestinal microbiome composition and the onset of cancer. Childhood cancer is still the predominant cause of death among children over a year in Western countries. However, a profound understanding of the changes in the composition of the microbiome in the onset or progression of childhood cancer is still lacking. Methods: We characterized the gut microbiota in a cohort of Norwegian children diagnosed with cancer using fecal samples before the onset of treatment. Samples were collected in the Norwegian Childhood Cancer Biobank (NCCB) and compared to a control group of children attending two diverse kindergartens in Oslo, Norway. The data of 16S rRNA gene amplicon sequencing were analyzed by non-metric multidimensional scaling (NMMS) of amplicon sequence variants (ASVs) relative abundance data. Results: Our results revealed 11 prevalent 16S rRNA gene sequence variants with significantly differential occurrence between the patient and the control groups. Eight of these taxa were depleted in children diagnosed with cancer, with three of these eight classified as Faecalibacterium prausnitzii. Conclusions: Our observations indicate that the gut microbiota may play an important role in understanding the physiological changes associated with childhood cancer. However, further studies are required to validate if variations in the microbial community could be used as an early indicator of the presence of cancer in the future.