Fusobacterium nucleatum (F. nucleatum) is a Gram-negative obligate anaerobe bacterium in the oral cavity and plays a role in several oral diseases, including periodontitis and gingivitis. Recently, several studies have reported that the level of F. nucleatum is significantly elevated in human colorectal adenomas and carcinomas compared to that in adjacent normal tissue. Several researchers have also demonstrated that F. nucleatum is obviously associated with colorectal cancer and promotes the development of colorectal neoplasms. In this review, we have summarized the recent reports on F. nucleatum and its role in colorectal cancer and have highlighted the methods of detecting F. nucleatum in colorectal cancer, the underlying mechanisms of pathogenesis, immunity status, and colorectal cancer prevention strategies that target F. nucleatum.

The gut microbiome plays an indispensable role in the occurrence and progression of various diseases. However, its ability to predict gastric cancer (GC) and liver metastasis (GCLM) has not been fully identified.

The proximal and distal subsites of colorectal cancer (CRC) have distinct differences in their embryonic origin, epidemiology, and prognosis. Therefore, they are not considered as the same disease. However, the possible difference in microbial characterization of the two subsites of CRC is still unclear. In this study, we explored tumor microbiota diversity and composition difference in patients with proximal (N = 187) and distal CRCs (N = 142). This was carried out on cancer tissues and adjacent tissues using bacterial 16S rRNA sequencing. The Kaplan–Meier method was used to analyze the correlation between differential flora and overall survival rate of the patients. It was found that there were significant differences in tumor microbial characteristics between the proximal and distal CRC tissues. The microbiota communities were distinctly richer in the proximal colon tumor tissues than in the distal CRC tissues. Microbial diversity and structure were relatively constant in the paracancerous normal tissues of the proximal and distal colorectum. Generally, microbial communities of CRC tumor tissues were composed of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Alpha diversity in the proximal and distal CRC tumor tissues was closely related to specific microflora. The abundance of Fusobacteria was associated with age of patient, tumor diameter, and tumor microsatellite instability (MSI) status of the patients. Moreover, Fusobacteria enrichment was associated with poor prognosis especially in patients with proximal colon cancers, but not in patients with distal CRC. In conclusion, proximal and distal subsites of the CRC present distinct microbiota diversity and community structures. The differences indicate that there are different risk factors across anatomical subsites of CRC, which may provide a new strategy for precise prevention and treatment of CRC in the future.

The alterations in gut bacteria are closely related to colorectal cancer. However, studies on adenoma are still scarce. Besides, the associations of gut viruses with colorectal tumor, and the interactions of bacteria with viruses in colorectal tumors are still under exploration. Therefore, a metagenomic sequencing of stool samples from patients with colorectal adenoma (CRA), colorectal cancer (CRC), and healthy controls was performed to identify changes in gut microbiome in patients with colorectal tumors. Five CRC-enriched bacteria (Peptostreptococcus stomatis, Clostridium symbiosum, Hungatella hathewayi, Parvimonas micra, and Gemella morbillorum) were identified as a diagnostic model to identify CRC patients, and the efficacy of the diagnostic model was verifiable in 1523 metagenomic samples from ten cohorts of eight different countries. We identified the positive association of Bacteroides fragilis with PD-L1 expression and PD-1 checkpoint pathway, providing a possible direction for studying bacterial carcinogenesis mechanisms. Furthermore, the increased interactions within the microbiome in patients may play roles in the development of CRC. In conclusion, this study identified novel microbiota combinations with discrimination for colorectal tumor, and revealed the potential interactions of gut bacteria with viruses in the adenoma-carcinoma sequence, which implies that the microbiome, but not only bacteria, should be paid more attention in further studies.

Purpose: This study aimed to evaluate the efficacy and safety of camrelizumab plus apatinib with or without stereotactic body radiotherapy (SBRT) as first-line therapy for patients with hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT). Patients and Methods: This is a multicenter, open-label, noncomparative, randomized trial that recruited patients with HCC with type II/III/IV PVTT, who had not previously received systemic therapy. Patients were randomly assigned (2:1) to receive camrelizumab (200 mg, every 3 weeks) and apatinib (250 mg, every day) with or without SBRT [95% planning target volume (PTV), 36–40 Gy/6–8 Gy]. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), duration of response, time to progression, and safety. Results: Sixty patients were enrolled and randomly assigned to two prospective cohorts. Median OS were 12.7 months [95% confidence interval (CI), 10.2–not available (NA)] and 8.6 months (95% CI, 5.6–NA), and median PFS were 4.6 months (95% CI, 3.3–7.0) and 2.5 months (95% CI, 2.0–7.6) for the SBRT and non-SBRT cohorts, respectively. The ORR and DCR were 47.5% and 72.5% in the SBRT cohort, and 20.0% and 40.0% in the non-SBRT cohort. The most common treatment-related adverse events of any grade were hypertension (55.0%), hand-foot syndrome (51.7%), and leukopenia (50.0%). Grade ≥ 3 was reported in 13 (21.7%) patients. Conclusions: First-line treatment with camrelizumab–apatinib combined with or without SBRT showed clinical benefits in patients with HCC with PVTT, with an acceptable safety profile. Thus, these combination regimens may be potential options for such patients.