Takumi Tochio

Introduction. Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide.Gap statement. Monitoring of HCC and predicting its immunotherapy responses are challenging.Aim. This study explored the potential of the gut microbiome for HCC monitoring and predicting HCC immunotherapy responses.Methods. DNA samples were collected from the faeces of 22 patients with HCC treated with atezolizumab/bevacizumab (Atz/Bev) and 85 healthy controls. The gut microbiome was analysed using 16S rRNA next-generation sequencing and quantitative PCR (qPCR).Results. The microbiomes of patients with HCC demonstrated significant enrichment of Lactobacillus, particularly Lactobacillus fermentum, and Streptococcus, notably Streptococcus anginosus. Comparative analysis between Atz/Bev responders (R) and non-responders (NR) revealed a higher abundance of Bacteroides stercoris in the NR group and Bacteroides coprocola in the R group. Using qPCR analysis, we observed elevated levels of S. anginosus and reduced levels of 5α-reductase genes, essential for the synthesis of isoallolithocholic acid, in HCC patients compared to controls. Additionally, the analysis confirmed a significantly lower abundance of B. stercoris in the Atz/Bev R group relative to the NR group.Conclusions. The gut microbiome analysis and specific gene quantification via qPCR could provide a rapid, less invasive, and cost-effective approach for assessing the increased risk of HCC, monitoring patient status, and predicting immunotherapy responses.

Less than half of all patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) respond to chemotherapy, and the prognosis of PDAC is poor, which may be mediated by the gut microbiota. We investigated the clinical improvement effects of 1-kestose, a fructooligosaccharide, on PDAC chemotherapy in this single-center, randomized, controlled pilot trial conducted at Fujita Health University Hospital, which enrolled patients with PDAC. The trial included 1-kestose administration and non-administration groups. The 1-kestose group received 9 g of 1-kestose daily for 12 weeks, and their blood markers, imaging studies, physical findings, and gut microbiota were evaluated. In the 1-kestose administration group, the cancer marker CA19-9 significantly decreased, and there was a reduction in the neutrophil-to-lymphocyte ratio (NLR). There was also suppression of the reduction of albumin levels and of an increase in C-reactive protein. Additionally, Escherichia coli, which typically increases in PDAC, significantly decreased in the 1-kestose group. Thus, 1-kestose altered the gut microbiota and improved the prognostic factors for PDAC. Large-scale, long-term trials of 1-kestose interventions for PDAC are thus warranted to improve the prognosis of PDAC.