Existence and distribution of the microbiome in tumour tissues of children with hepatoblastoma.

Cancer microbiota have recently been demonstrated in several cancer types. The microbiome enhances inflammation in the cancer microenvironment and affects the disease pathology by regulating tumourigenesis, cancer progression, and chemotherapy resistance. Hepatoblastoma (HB), the most common childhood malignant tumour, is a malignant embryonic tumour. However, the pathogenesis and molecular basis of HB remain poorly understood. In this study, to explore the existence and distribution of the microbiome in tumour tissues and adjacent non-tumour tissues of children with HB, we mainly performed 16S rDNA sequencing, and the results showed that the diversity and abundance of the microbiome in children with HB were significantly different between HB tumours and adjacent non-tumour tissues (p < 0.01). At the phylum level, the dominant microbiome in the tumour tissues were Proteobacteria, Bacteroidetes, and Firmicutes. At the genus level, Ruminococcus was more abundant in HB tumours than in the adjacent non-tumour tissues. Simultaneously, the abundances of Bacteroides, Parabacteroides, Lachnospiracea-NK4A136, and Alistipes in HB tumours were lower than those in the adjacent non-tumour tissues. In addition, Romboutsia strongly correlated with alpha-fetoprotein, an important indicator of HB. Sphingomonas was abundant in primary HB tumours, whereas Oscillibacter and Pandoraea were abundant in metastatic HB tumours. However, whether these bacteria are associated with HB needs further evaluation. Therefore, we identified the microbiome that correlated with the occurrence and development of HB. Ruminococcus and Romboutsia were identified as potential bacterial markers of HB tumours. To conclude, we found that HB also contains cancer microbiome, and it is necessary to shed light on the microbiome characteristics of HB in the future.