BackgroundHepatocellular carcinoma (HCC) is one of the most common malignant tumors, and many patients are diagnosed with advanced disease. The treatment of advanced liver cancer has made significant strides in recent years, owing to the practice of immunotherapy drugs. Numerous studies have been published on immunotherapy for HCC; however, no relevant bibliometric study has been published. This study aims to gain a better understanding of the current situation and to identify potential new research directions by conducting a bibliometric analysis on immunotherapy for HCC.MethodsWe searched the Web of Science Core Collection (WoSCC) for articles related to immunotherapy for HCC. Three software (VOSviewer, CiteSpace, and python) were primarily used to assess the contribution and co-occurrence relationships of various countries/regions, institutes, journals, and, authors as well as to identify research hotspots and promising future trends in this research field.ResultsA total of 1,641 English articles published between 2011 and 2020 were collected, with the number of articles increasing nearly every year. The majority of publications originated from China (n = 893, 54.42%), followed by the United States and Japan. The Sun Yat-sen University contributed the most publications (n = 97, 5.91%). Nakatsura Tetsuya (n = 26) and Llovet JM (n = 366) were ranked first in the top ten authors and co-cited authors. Cancer Immunology Immunotherapy was the most productive academic journal on immunotherapy for HCC [n = 46, 2.80%; impact factor (IF) 2020 = 6.9679]. Aggregation and identification of critical nodes in the co-cited network demonstrated a shift in the field of HCC immunotherapy. Initially, the hotspots were predominantly “glypican-3”, “cytokine-induced killer cells”, and “ny-eso-1”, while the emphasis has shifted in recent years to “landscape”, “camrelizumab”, “combination therapy”, and “immune score”.ConclusionIncreased attention has been paid to HCC with the advancement of immunotherapy. At the moment, the most active frontiers are focused on better understanding the immunological landscape of liver cancer, screening the population that can benefit from immunotherapy, and the clinical application of immune checkpoint inhibitors, particularly in combination with other therapeutic options (such as local therapy and targeted therapy).

Background Gut microbiota and microbe-derived metabolites are involved in the development of HCC. Bile acids (BAs) are the most important gut microbiota-modulated endogenous signaling molecules. Methods We tested serum bile acid levels and gut microbiome compositions in patients with HCC, chemical-induced HCC mouse models (DEN-HCC mice) and mouse orthotopic implanted liver tumor models with vancomycin treatment (vancomycin-treated mice). Then, we screened an important kind of HCC-related BAs, and verified its effect on the growth of HCC in vivo and in vitro. Results We found that the remarkably decreasing percentages of serum secondary BAs in the total bile acids of patients and DEN-HCC mice, especially, conjugated deoxycholic acids (DCA). The relative abundance of the bile salt hydrolase (BSH)-rich bacteria (Bifidobacteriales, Lactobacillales, Bacteroidales, and Clostridiales) was decreased in the feces of patients and DEN-HCC mice. Then, in vancomycin-treated mice, vancomycin treatment induced a reduction in the BSH-rich bacteria and promoted the growth of liver tumors. Similarly, the percentage of conjugated DCA after vancomycin treatment was significantly declined. We used a kind of conjugated DCA, Glyco-deoxycholic acid (GDCA), and found that GDCA remarkably inhibited the growth of HCC in vivo and in vitro. Conclusions We conclude that the remarkably decreasing percentages of serum conjugated DCA may be closely associated with HCC, which may be induced by the reducing gut BSH-rich bacteria. The mechanisms may be correlated with conjugated DCA directly inhibiting the growth and migration of HCC cells.

The features and significance of somatic mutation profiles in hepatocellular carcinoma (HCC) have not been completely elucidated to date. In this study, 39 tumor specimens from HCC patients were collected for gene variation analysis by next-generation sequencing (NGS), and a correlation analysis between mutated genes and clinical characteristics was also conducted. The results were compared with genome data from cBioPortal database. Our study found that T > G/A > C transversions (Tv) and C > T/G > A transitions (Ti) were dominant. The sequence variations of TP53, MUC16, MUC12, MUC4 and others, and the copy number variations (CNVs) of FGF3, TERT, and SOX2 were found to be more frequent in our cohort than in cBioPortal datasets, and they were highly enriched in pathways in cancer and participated in complex biological regulatory processes. The TP53 mutation was the key mutation (76.9%, 30/39), and the most common amino acid alteration and mutation types were p.R249S (23.5%) and missense mutation (82.3%) in the TP53 variation. Furthermore, TP53 had more co-mutations with MUC17, NBPF10, and AHNAK2. However, there were no significant differences in clinical characteristics between HCC patients with mutant TP53 and wild-type TP53, and the overall survival rate between treatment via precision medication guided by NGS and that via empirical medication (logrank p = 0.181). Therefore, the role of NGS in the guidance of personalized targeted therapy, solely based on NGS, may be limited. Multi-center, large sample, prospective studies are needed to further verify these results.

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Gut microbiota and microbe-derived metabolites are involved in the development of HCC. Bile acids (BAs) are the most important gut microbiota-modulated endogenous signaling molecules. First, we tested serum bile acid levels and gut microbiome compositions in patients with HCC, chemical -induced HCC mouse models (DEN-HCC mice) and mouse orthotopic implanted liver tumor models with vancomycin treatment (Vancomycin-treated mice ). Then, we screened an important kind of HCC-related BAs, and verified its effect on the growth and migration of HCC cells. We found that the remarkably decreasing percentages of serum secondary BAs in the total bile acids of patients and DEN-HCC mice, especially, conjugated deoxycholic acids (DCA). The relative abundance of the bile salt hydrolase (BSH)-rich bacteria (Bifidobacteriales, Lactobacillales, Bacteroidales, and Clostridiales) was decreased in the feces of patients and DEN-HCC mice. Then, in Vancomycin-treated mice, vancomycin treatment induced a reduction in the BSH-rich bacteria and promoted the growth of liver tumors. Similarly, the percentage of conjugated DCA after vancomycin treatment was significantly declined. We used a kind of conjugated DCA, Glyco-deoxycholic acid (GDCA), to treat human SUN-449 and HepG2 HCC cell lines, and found that GDCA remarkably inhibited the proliferation and migration of HCC cells. We conclude that the remarkably decreasing percentages of serum conjugated DCA may be closely associated with HCC, which may be induced by the reducing gut BSH-rich bacteria. The mechanisms may be correlated with conjugated DCA directly inhibiting the growth and migration of HCC cells.