16S rRNA gene analysis reveals differentially abundant Actinobacteria, Firmicutes, and Proteobacteria in the tumors and adjacent healthy tissues of patients with hepatocellular carcinoma

AbstractBackground Dysbiosis of the gut-liver axis poses a risk of increased influx of microbes and/or their metabolites into the liver, and such increased influx may constitute a risk factor for the development of hepatocellular carcinoma (HCC). In this pilot study, we compared the microbiomes in HCC tumors and adjacent healthy tissues. Method We examined the HCC tumors and adjacent healthy tissues from 19 patients diagnosed with HCC. The hypervariable V3–V4 regions of the microbial 16S rRNA gene in these samples were sequenced following amplification via polymerase chain reaction. The sequencing data were analyzed using QIIME2 and the linear discriminant analysis effect size (LEfSe) algorithm on the Galaxy Platform. The samples were categorized according to their microbial diversity at the genus level (p ≤ 0.050). Results The liver tissues from HCC patients with/without capsule invasion presented with lower alpha diversity at the genus level (Observed Features metrics,p = 0.028). Metagenomic profiling revealed thatStaphylococcus,Atopobium,Pseudomonadaceae,Propionibacterium, andCorynebacteriumwere enriched in the HCC tumors from patients with capsule invasion, whereasPseudomonaswas scant in the HCC tumors from patients without capsule invasion. An increased abundance ofActinobacteria,Firmicutes, andProteobacteriawas observed in the adjacent healthy tissues from patients with various stages of HCC. Conclusions The presence of various types of microbial 16S rRNAs in HCC tumors and adjacent healthy tissues indicates the presence of various microbial communities therein. HCC is presumably associated with an inordinate gut microbiota, which may affect the development of HCC. The increased microbial influx into the liver in HCC patients may constitute an early risk factor for the progression of HCC. Accordingly, our results may provide microbiota-oriented therapeutic targets for personalized treatment approaches in HCC.