Leveraging Fecal Microbial Markers to Improve the Diagnostic Accuracy of the Fecal Immunochemical Test for Advanced Colorectal Adenoma

Systematic scoping review: Use of the faecal immunochemical test residual buffer to enhance colorectal cancer screening

BACKGROUND

The faecal immunochemical test (FIT) is an inexpensive and convenient modality to screen for colorectal cancer. However, its one-time sensitivity for detecting colorectal cancer and cancer precursors is limited. There is growing interest in using the non-haemoglobin contents of FIT residual buffer to enhance colonic neoplasia detection.

AIM

To establish from the literature a framework to catalogue candidate biomarkers within FIT residual buffer for non-invasive colorectal cancer screening.

METHODS

The search strategy evaluated PubMed, Scopus, Web of Science, Embase, and Google Scholar for publications through 25 October 2023, with search terms including FIT, buffer, OC-sensor, biomarkers, microbiome, microRNA (miR), colon, rectum, screening, neoplasm, and early detection. Studies employing home-based collection samples using quantitative FIT first processed for haemoglobin were included. One author reviewed all articles; a second author completed a 20% full-text audit to ensure adherence to eligibility criteria.

RESULTS

A broad search yielded 1669 studies and application of eligibility criteria identified 18 relevant studies. Multiple protein, DNA/RNA, and microbiome biomarkers (notably haptoglobin, miR-16, miR-27a-3p, miR-92a, miR-148a-3p, miR-223, miR-421, let-7b-5p, and Tyzzerella 4) were associated with colorectal neoplasia. Furthermore, studies highlighted the short-term stability of biomarkers for clinical use and long-term stability for research purposes.

CONCLUSIONS

This scoping review summarises the framework and progress of research on stability of biomarkers in FIT residual buffer and their associations with colorectal neoplasia to guide opportunities for further confirmatory studies to enhance colorectal cancer screening.

Cross-sectional risk models using quantitative fecal hemoglobin in colorectal cancer screening: a systematic review

INTRODUCTION

Fecal Immunochemical Testing (FIT) is a central tool in colorectal cancer (CRC) screening. To improve the selection of individuals for colonoscopy, risk models combining FIT with additional CRC risk factors have been developed. This systematic review aims to provide an overview of the current noninvasive FIT-based risk models for CRC screening to facilitate future implementation.

METHODS

We performed a systematic literature search for risk models that combined quantitative fecal hemoglobin with clinical data or noninvasive biomarkers and that were intended for CRC screening. Risk of bias was assessed using the PROBAST tool.

RESULTS

Twenty risk models reported across 29 publications were included. The overall risk of bias was high. In studies that compared risk models to FIT, 11/12 (92%) risk models had a significantly higher c-statistic than FIT only. 16/20 risk models (80%) had not been externally validated and only one model has been implemented so far.

CONCLUSION

FIT-based risk models have the potential to improve the yield of CRC screening. Unfortunately, all included publications had a high risk of bias and most risk models have not yet been externally validated. The prospect of improved CRC screening with risk models should encourage more rigorous evaluation in existing screening programs.

Immuno-stimulatory activity of Astragalus polysaccharides in cyclophosphamide-induced immunosuppressed mice by regulating gut microbiota

Evidence has indicated the immune-stimulatory effect of Astragalus polysaccharides (APS), yet it remains unknown whether the potential mechanism is associated with gut microbiota. In this study, we aimed to investigate the role of gut microbiota in APS-initiated immune-enhancing activity in mice. BALB/c mice were injected with cyclophosphamide to establish a mouse immunosuppression model. We found that APS significantly ameliorated the immunosuppression in mice, indicative of the increased immune organ indices, the promoted proliferation of immune cells, and the up-regulated intestinal inflammation. Western blot analysis demonstrated that APS treatment significantly activated Toll-like receptor 4 (TLR4) and mitogen-activated protein kinase (MAPK) pathways in the intestine. By 16S rDNA sequencing, APS treatment reversed the gut microbiota dysbiosis in immunocompromised mice. At the genus level, APS increased the abundance of bacteria (like Lactobacillus, Bifidobacteria, Roseburia, and Desulfovibrio) and decreased the content of several bacteria (like Oscillibacter, Tyzzerella, and Lachnoclostridium). However, APS had no immune-enhancing effect on immunocompromised mice with gut microbiota depletion. In conclusion, APS can enhance immune responses in immunocompromised mice by modulating gut microbiota dysbiosis.

Tissue vs. Fecal-Derived Bacterial Dysbiosis in Precancerous Colorectal Lesions: A Systematic Review

Alterations in gut microbiota play a pivotal role in the adenoma-carcinoma sequence. However, there is still a notable lack of the correct implementation of tissue and fecal sampling in the setting of human gut microbiota examination. This study aimed to review the literature and to consolidate the current evidence on the use of mucosa and a stool-based matrix investigating human gut microbiota changes in precancerous colorectal lesions. A systematic review of papers from 2012 until November 2022 published on the PubMed and Web of Science databases was conducted. The majority of the included studies have significantly associated gut microbial dysbiosis with premalignant polyps in the colorectum. Although methodological differences hampered the precise fecal and tissue-derived dysbiosis comparison, the analysis revealed several common characteristics in stool-based and fecal-derived gut microbiota structures in patients with colorectal polyps: simple or advanced adenomas, serrated lesions, and carcinomas in situ. The mucosal samples considered were more relevant for the evaluation of microbiota's pathophysiological involvement in CR carcinogenesis, while non-invasive stool sampling could be beneficial for early CRC detection strategies in the future. Further studies are required to identify and validate mucosa-associated and luminal colorectal microbial patterns and their role in CRC carcinogenesis, as well as in the clinical setting of human microbiota studies.

The global research of microbiota in colorectal cancer screening: a bibliometric and visualization analysis

Aims

We conducted bibliometric and visualization analyses to evaluate the current research status, hotspots, and trends related to the human microbiota markers in colorectal cancer screening.

Methods

The related studies were acquired from the Web of Science Core Collection (WoSCC) database on 5 January 2023. Analyses of the co-occurrence and cooperation relationships between the cited authors, institutions, countries/regions, cited journals, cited articles, and keywords in the studies were carried out using CiteSpace 5.8.R3 software and the Online Analysis platform of Literature Metrology. Additionally, relevant knowledge graphs were drawn to perform visualization analyses; a keywords cluster analysis and a burst analysis were also conducted.

Results

After analyzing 700 relevant articles, this bibliometric analysis found that the annual publications showed an increasing trend from 1992 to 2022. Yu Jun from the Chinese University of Hong Kong had the highest cumulative number of publications, whereas Shanghai Jiao Tong University was the most productive institution. China and the USA have contributed the largest number of studies. The keywords frequency analysis demonstrated that "colorectal cancer," "gut microbiota," "Fusobacterium nucleatum," "risk," and "microbiota" were the most frequent keywords, and the keywords cluster analysis found that the current hotspots were as follows: (a) the precancerous lesions of colorectal cancer (CRC) that need to be screened, such as inflammatory bowel disease (IBD) and advanced adenoma, (b) the gut-derived microbiome for CRC screening, and (c) the early detection of CRC. The burst analysis further showed that the combination of microbiomics with metabolomics might be the future research trend in the field of CRC screening.

Conclusion

The findings of the current bibliometric analysis firstly provide an insight into the current research status, hotspots, and future trends in the field of CRC screening based on the microbiome; the research in this field is becoming more in-depth and diversified. Some human microbiota markers, especially "Fusobacterium nucleatum," are promising biomarkers in CRC screening, and a future hotspot might be the combined analysis of microbiomics and metabolomics for CRC risk screening.

A systematic review of microbiome-derived biomarkers for early colorectal cancer detection

Increasing evidence suggests a role of the gut microbiome in the development of colorectal cancer (CRC) and that it can serve as a biomarker for early diagnosis. This review aims to give an overview of the current status of published studies regarding the microbiome as a screening tool for early CRC detection. A literature search was conducted using PubMed and EMBASE in August 2022. Studies assessing the efficacy of microbiome-derived biomarkers based on noninvasive derived samples were included. Not relevant studies or studies not specifying the stage of CRC or grouping them together in the analysis were excluded. The risk of bias for screening tools was performed using the QUADAS-2 checklist. A total of 28 studies were included, ranging from 2 to 462 for CRC and 18 to 665 advanced adenoma patient inclusions, of which only two investigated the co-metabolome as biomarker. The diagnostic performance of faecal bacteria-derived biomarkers had an AUC ranging from 0.28-0.98 for precursor lesions such as advanced adenomas and 0.54-0.89 for early CRC. Diagnostic performance based on the co-metabolome showed an AUC ranging from 0.69 - 0.84 for precursor lesions and 0.65 - 0.93 for early CRC. All models improved when combined with established clinical early detection markers such as gFOBT. A high level of heterogeneity was seen in the number of inclusions and methodology used in the studies. The faecal and oral gut microbiome has the potential to complement existing CRC screening tools, however current evidence suggests that this is not yet ready for routine clinical use.

Habitual Diet Pattern Associations with Gut Microbiome Diversity and Composition: Results from a Chinese Adult Cohort

The influence of long-term diet on gut microbiota is an active area of investigation. The present work aimed to explore the associations between habitual diet patterns and gut microbiota in a large sample of asymptomatic Chinese adults. The gut microbiome was profiled through the sequencing of the 16S rRNA gene in stool samples from 702 Chinese adults aged 50–75 years who underwent colonoscopies and were diagnosed to be free of colorectal neoplasm. Long-term dietary consumption was assessed through a food-frequency questionnaire. The microbial associations with specific food groups and the posteriori dietary pattern were tested using the Kruskal–Wallis H test, permutational ANOVAs, and multivariate analyses with linear models. The Shannon indexes generally shared similar levels across different food intake frequency groups. Whole grain and vegetable intakes totally explained 1.46% of the microbiota compositional variance. Using the data-driven posteriori approach, a general dietary pattern characterized by lower intakes of refined grains was highlighted to be associated with higher abundances of the genus Anaerostipes and a species of it. We also observed 17 associations between various food group intakes and specific genera and species. For instance, the relative abundances of the genus Weissella and an uncultured species of it were negatively associated with red meat intake. The results of this study support the idea that the usual dietary consumption measured by certain food items or summary indexes is associated with gut microbial features. These results deepen the understanding of complex relationships of diet and gut microbiota, as well as their implications for gut microbiome studies of human chronic diseases.