稲村 健太郎

Background: Enterotoxigenic Bacteroides fragilis (ETBF) carries the bft toxin gene, which influences the host immune response and inflammatory pathways and promotes colorectal cancer (CRC). This study investigated the potential role of ETBF in CRC liver metastasis. Methods: We reviewed the records of 226 consecutive patients who underwent curative-intent (R0) resection of CRC liver metastases. ETBF DNA in fresh-frozen metastasis specimens was quantified using droplet digital PCR (ddPCR). Patients were grouped into very-low (≤80%; N = 178), low (80-90%; N = 24), and high (>90%; N = 24) ETBF-DNA groups. Three tissue cores per specimen were stained for CD8, CD4, CD20, FOXP3, CD68, and CD163, and immune-cell densities were measured digitally (cells/mm2). Results: ETBF DNA was detected in 219 of 226 lesions (96.9%). The densities of cytotoxic CD8+ T-cells, effector CD4+ T-cells, CD20+ B-cells, and CD163+ macrophages did not differ significantly by ETBF-DNA group (Ptrend all > 0.12). FOXP3+ regulatory T-cells (Tregs) decreased (Ptrend = 0.010), and CD68+ macrophages increased (Ptrend = 0.020) as ETBF-DNA levels increased. ETBF-DNA levels in CRC liver metastases were not associated with disease-free survival or overall survival or serum C-reactive protein levels. Conclusions: ETBF was present in almost all CRC liver metastases. Higher ETBF levels were associated with a tumor-immune microenvironment enriched in CD68+ macrophages and deficient in FOXP3+ Tregs, suggesting that ETBF facilitates immune evasion without loss of effector lymphocytes. Although ETBF-DNA levels did not predict survival in this single-center cohort, the potential role of ETBF in immune remodeling and as a candidate biomarker and therapeutic target in metastatic CRC warrants further study.

In hepatocellular carcinoma (HCC), CD147 expression contributes to tumor malignancy; however, its relationship with the tumor-immune microenvironment (TIME) remains unclear. This study aimed to elucidate the clinicopathological characteristics associated with CD147 expression in HCC and investigate its association with the TIME, specifically its association with tumor-infiltrating lymphocytes (TILs) and oncostatin M (OSM). Using 397 HCC specimens from patients undergoing curative-intent resection, we assessed CD147 expression in tumor cells and quantified OSM-positive cells and various TILs (CD8+, CD4+, FOXP3+, and CD20+ cells) in the TIME. Using tissue microarrays, these assessments were performed through immunohistochemical analysis. We investigated the associations between CD147 expression status, the density of OSM-positive cells, and the densities of various TILs. High CD147 expression, found in 332 specimens (83.6%), was associated with advanced clinical stage (P = 0.029), fibrosis (P = 0.036), and higher densities of FOXP3+ cells (P = 0.0039), CD4+ cells (P = 0.0012), and OSM-positive cells (P = 0.0017). In CD147-high tumors, OSM-positive cell density was associated with all assessed TIL subsets (CD8+, CD4+, FOXP3+, and CD20+ cells; all Ps < 0.001), whereas in CD147-low tumors, OSM-positive cell density was associated only with FOXP3+ cells (P = 0.0004). In HCC, CD147 expression is associated with an immunosuppressive TIME, characterized by increased FOXP3+ regulatory T cells and a correlation with OSM-positive cells. These results elucidate the potential mechanisms through which CD147 facilitates tumor-immune evasion, suggesting the CD147 - OSM axis as a promising target for therapeutic intervention in HCC.

BACKGROUND: Small cell carcinoma (SmCC) of the bladder is a rare and aggressive malignancy. Characterizing transcription factor (TF)-defined subtypes may provide insights into its biology and inform targeted therapies. This study investigates lineage-specific TF expression in bladder SmCC, its association with clinicopathological features, and comparisons with prostate SmCC. METHODS: A retrospective analysis was conducted on 9 cases of bladder SmCC and 6 cases of prostate SmCC diagnosed at a single cancer hospital in Japan. Immunohistochemistry was performed for lineage-specific TFs (ASCL1, NEUROD1, POU2F3, and YAP1) and neuroendocrine and other markers. Statistical comparisons were made using Fisher's exact test and independent samples t-tests. RESULTS: Combined SmCC morphology, including urothelial carcinoma (UC) (5 cases) and adenocarcinoma (2 cases), was more frequent in bladder SmCC than in prostate SmCC (78% [7 of 9 cases] vs. 17% [1 of 6 cases], p = 0.041). NEUROD1 was more frequently expressed in bladder SmCC than in prostate SmCC (67% [6 of 9 cases] vs. 0% [0 of 6 cases]; p = 0.028). NEUROD1 expression was more frequent in combined SmCC and UC bladder tumors than in other bladder SmCC tumors (100% [5 of 5 cases] vs. 25% [1 of 4 cases], p = 0.048). Conversely, HNF4A expression was absent in all combined SmCC and UC bladder tumors (0 of 5) but present in 75% (3 of 4) of other bladder SmCC tumors (p = 0.048). In 2 cases of bladder SmCC, NEUROD1 and POU2F3 were expressed in a mutually exclusive manner, with neuroendocrine markers expressed only in the NEUROD1-expressing component. CONCLUSIONS: NEUROD1 is characteristically expressed in bladder SmCC, especially in SmCC combined with UC, suggesting a distinct phenotype from prostate SmCC. These findings highlight the potential for TF-based classification to improve diagnostic accuracy and inform therapeutic strategies.

Colibactin, a genotoxin produced by Escherichia coli strains harboring the polyketide synthetase (pks) gene cluster, causes DNA damage and somatic mutations. pks+E. coli is enriched in primary colorectal cancer (CRC) and is associated with clonal driver mutations, but its role in CRC liver metastasis is unclear. We assessed the association of pks+ E. coli in CRC liver metastasis tissues with systemic and local immune responses and the number of organs involved in recurrence using specimens and clinicopathological data from 239 patients with CRC liver metastasis who underwent metastasectomy. The levels of pks+E. coli in fresh-frozen specimens were quantified as "very low" (<50th percentile), "low" (50th to 75th percentiles), and "high" (>75th percentile) using a digital PCR. Immunohistochemical analysis of tumor-infiltrating immune cells was performed using tissue microarrays. Systemic inflammation was evaluated using serum C-reactive protein (CRP) levels. pks+E. coli was detected in 66.7% (157 of 239) liver metastasis tissues. Higher levels of pks+E. coli were associated with decreased serum CRP levels and reduced densities of CD4+ cells and CD163+ cells in the tumor-immune microenvironment. The "high" pks+ E. coli group had fewer metastatic organs involved than the "very low" pks+ E. coli group (mean number of organs: 1.00 vs. 1.23). These findings suggest that pks+E. coli play a modulating role in CRC metastasis.

The presence of Fusobacterium nucleatum is associated with an immunosuppressive tumor immune microenvironment (TIM) in primary colorectal cancer (CRC), contributing to tumor progression. Its persistence in CRC liver metastasis tissues raises questions about its role in modulating local and systemic immune responses and influencing recurrence patterns. This retrospective cohort study of 218 patients with CRC liver metastasis investigated the association of F. nucleatum in CRC liver metastasis tissues with systemic inflammation, TIM alterations, and the number of metastatic organs involved in recurrence. Two-step polymerase chain reaction (PCR), including digital PCR, detected F. nucleatum in 42% (92/218) of fresh-frozen specimens of CRC liver metastases. Compared with the F. nucleatum-none group, the F. nucleatum-high group showed higher C-reactive protein levels (0.82 vs. 0.22 mg/dL; Ptrend = 0.02), lower numbers of CD8+ cells (33.2 vs. 65.3 cells/mm2; Ptrend = 0.04) and FOXP3+ cells (11.3 vs. 21.7 cells/mm2; Ptrend = 0.01) in the TIM, and a greater number of metastatic organs involved in recurrence (1.6 vs. 1.1; p < 0.001). The presence of F. nucleatum in CRC liver metastasis tissues was associated with increased systemic inflammation, TIM alterations, and a greater number of metastatic organs involved in recurrence. These findings suggest a potential contribution of F. nucleatum to the metastatic propensity of CRC cells and could inform future research to enhance understanding of the interaction between tumor, host, and microbes in the metastatic process.

Inverted urothelial papilloma (IUP) is a benign neoplasm characterized by a downgrowth of the urothelium beneath the surface of morphologically normal urothelial cells; however, the molecular features of IUP and their association with clinicopathological characteristics are unclear. In this study, we aimed to investigate the mutational landscape, clinicopathological features, genotype-phenotype associations, and spread patterns of IUP. We performed targeted next-generation sequencing of 39 consecutive IUP cases, the largest series investigated to date, and identified oncogenic driver mutations in RAS family genes in 34 cases (87%). HRAS mutations were the most prevalent (28 cases), which included Q61R (15 cases), followed by KRAS (5 cases) and NRAS (1 case) mutations. Characteristic mutations observed in urothelial carcinoma, including those in FGFR3, TP53, or the TERT promoter, were absent. HRAS-mutated IUPs were associated with a history of smoking (P = 0.017) and streaming morphology (P < 0.001), corresponding to the trabecular subtype. In contrast, all KRAS-mutated IUPs occurred in never-smoking patients (P = 0.001) and showed cystic changes in morphology (P = 0.005), corresponding to the glandular subtype. RAS Q61R immunohistochemistry visually revealed the neoplastic nature of the overlying cells and distinct spread patterns of IUP cells within the surface, including pseudoinfiltrative spread. No recurrence or carcinoma development was observed in any of the IUP cases during the follow-up period. Thus, we confirmed the importance of RAS pathway activation in IUP pathogenesis, an association between RAS family gene mutations and IUP subtypes, and the spread patterns of IUP cells within the surface.

The microbiota is widely recognized to influence diverse biological processes, including metabolism, neurological and cardiovascular functions, the inflammatory response and immunity [...].

Cancer is generally regarded as a localised disease, with the well-established role of the tumour microenvironment. However, the realm of cancer goes beyond the tumour microenvironment, and cancer should also be regarded as a systemic and environmental disease. The exposome (ie, the totality of exposures), which encompasses diets, supplements, smoking, alcohol, other lifestyle factors, medications, etc, likely alters the microbiome (inclusive of bacteria, viruses, archaea, fungi, parasites, etc) and immune system in various body sites and influences tumour phenotypes. The systemic metabolic/inflammatory status, which is likely influenced by exposures and intestinal physiological changes, may affect tissue microenvironment of colorectum and any other organs. Germline genomic factors can modify disease phenotypes via gene-by-environment interactions. Although challenges exist, it is crucial to advance not only basic experimental research that can analyse the effects of exposures, microorganisms and microenvironmental components on tumour evolution but also interdisciplinary human population research that can dissect the complex pathogenic roles of the exposome, microbiome and immunome. Metagenomic, metatranscriptomic and metabolomic analyses should be integrated into well-designed population research combined with advanced methodologies of artificial intelligence and molecular pathological epidemiology. Ideally, a prospective cohort study design that enables biospecimen (such as stool) collection before disease detection should be considered to address reverse causation and recall biases. Robust experimental and observational research together can provide insights into dynamic interactions between environmental exposures, microbiota, tumour and immunity during carcinogenesis processes, thereby helping us develop precision prevention and therapeutic strategies to ultimately reduce the cancer burden.

The microbiota influences human health and the development of diverse diseases, including cancer. Microbes can influence tumor initiation and development in either a positive or negative manner. In addition, the composition of the gut microbiota affects the efficacy and toxicity of cancer therapeutics as well as therapeutic resistance. The striking impact of microbiota on oncogenesis and cancer therapy provides compelling evidence to support the notion that manipulating microbial networks represents a promising strategy for treating and preventing cancer. Specific microbes or the microbial ecosystem can be modified via a multiplicity of processes, and therapeutic methods and approaches have been evolving. Microbial manipulation can be applied as an adjunct to traditional cancer therapies such as chemotherapy and immunotherapy. Furthermore, this approach displays great promise as a stand-alone therapy following the failure of standard therapy. Moreover, such strategies may also benefit patients by avoiding the emergence of toxic side effects that result in treatment discontinuation. A better understanding of the host-microbial ecosystem in patients with cancer, together with the development of methodologies for manipulating the microbiome, will help expand the frontiers of precision cancer therapeutics, thereby improving patient care. This review discusses the roles of the microbiota in oncogenesis and cancer therapy, with a focus on efforts to harness the microbiota to fight cancer.

Immunotherapy, which shows great promise for treating patients with metastatic malignancies, has dramatically changed the therapeutic landscape of cancer, particularly subsequent to the discovery of immune checkpoint inhibitors. However, the responses to immunotherapy are heterogeneous and often transient. More problematic is that a high proportion of patients with cancer are resistant to such therapy. Much effort has been expended to identify reliable biomarkers that accurately predict clinical responses to immunotherapy. Unfortunately, such tools are lacking, and our knowledge of the mechanisms underlying its efficacy and safety is insufficient. The microbiota is increasingly recognized for its influence on human health and disease. Microbes create a pro- or an anti-inflammatory environment through complex interactions with host cells and cytokines. Emerging evidence indicates that microbes alter the efficacy and toxicity of immunotherapy by modulating the host's local and systemic immune responses. It is therefore critically important to exploit the microbiota to develop biomarkers as well as to identify therapeutic targets that can be applied to cancer immunotherapy. This review provides insights into the challenges that must be addressed to achieve these goals.