Association of Combined Sero-Positivity to Helicobacter pylori and Streptococcus gallolyticus with Risk of Colorectal Cancer

Guideline for designing microbiome studies in neoplastic diseases

Oncobiosis has emerged as a key contributor to the development, and modulator of the treatment efficacy of cancer. Hereby, we review the modalities through which the oncobiome can support the progression of tumors, and the emerging therapeutic opportunities they present. The review highlights the inherent challenges and limitations faced in sampling and accurately characterizing oncobiome. Additionally, the review underscores the critical need for the standardization of microbial analysis techniques and the consistent reporting of microbiome data. We provide a suggested metadata set that should accompany microbiome datasets from oncological settings so that studies remain comparable and decipherable.

No evident causal association between Helicobacter pylori infection and colorectal cancer: a bidirectional mendelian randomization study

Observational studies have reported a correlation between Helicobacter pylori infection and colorectal cancer (CRC); however, the underlying cause has remained unclear. This research was aimed at determining whether there is a correlation between H. pylori infection and CRC by measuring the prevalence of H. pylori CagA antibodies and VacA antibodies. Using data from many genome-wide association studies (GWAS), we conducted a Mendelian randomization (MR) study with two sample GWAS. Then, we used bidirectional MR to evaluate the association between H. pylori infection and CRC for identifying causation. The most common method of analysis was the inverse variance-weighted technique. In addition, we performed supplementary analyses using the weighted median technique and MR-Egger regression. Horizontal pleiotropic outliers were identified and corrected using the MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) method. Genetically predicted anti-H. pylori IgG seropositivity was not causally associated with CRC [odds ratio (OR): 1.12; 95% confidence interval (CI): 0.98-1.27, P = 0.08] and neither were H. pylori VacA antibody levels (OR = 0.96, 95% CI: 0.90-1.02, P = 0.25) or H. pylori CagA antibody levels (OR = 1.00, 95% CI: 0.93-1.07, P = 0.92). Furthermore, reverse MR analysis did not reveal evidence for a causal effect of CRC on H. pylori infection. The weighted median, the MR-Egger method, and MR-PRESSO yielded identical results. Using genetic data, MR analysis showed there was no evidence for a causal association between seroprevalence of H. pylori infection and CRC. The relationship between H. pylori infection and CRC requires further research.

Gut microbiota and microbiota-derived metabolites in colorectal cancer: enemy or friend

Colorectal cancer (CRC) is a highly prevalent gastrointestinal cancer worldwide. Recent research has shown that the gut microbiota plays a significant role in the development of CRC. There is mounting evidence supporting the crucial contributions of bacteria-derived toxins and metabolites to cancer-related inflammation, immune imbalances, and the response to therapy. Besides, some gut microbiota and microbiota-derived metabolites have protective effects against CRC. This review aims to summarize the current studies on the effects and mechanisms of gut microbiota and microbiota-produced metabolites in the initiation, progression, and drug sensitivity/resistance of CRC. Additionally, we explore the clinical implications and future prospects of utilizing gut microbiota as innovative approaches for preventing and treating CRC.

Carcinogenic microbiota and its role in colorectal cancer development

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The main risk factors for CRC are family history of colon or rectal cancer, familial polyposis syndrome or hereditary nonpolyposis, and chronic inflammatory bowel diseases (ulcerative colitis and Crohn's disease). Recent studies show that the gastrointestinal microbiota play a significant role in colorectal carcinogenesis. In this review we present the microorganisms, whose influence on the development of CRC has been proven: Bacteroides fragilis, Clostridioides and Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Peptostreptococcus anaerobius, Streptococcus bovis group, and sulfate-reducing bacteria. Moreover, the carcinogenic mechanisms of action mediated by the above bacteria are laid out.

Dynamic liquid biopsy components as predictive and prognostic biomarkers in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide. The diagnosis, prognosis and therapeutic monitoring of CRC depends largely on tissue biopsy. However, due to tumor heterogeneity and limitations such as invasiveness, high cost and limited applicability in longitudinal monitoring, liquid biopsy has gathered immense attention in CRC. Liquid biopsy has several advantages over tissue biopsy including ease of sampling, effective monitoring, and longitudinal assessment of treatment dynamics. Furthermore, the importance of liquid biopsy is signified by approval of several liquid biopsy assays by regulatory bodies indicating the powerful approach of liquid biopsy for comprehensive CRC screening, diagnostic and prognostics. Several liquid biopsy biomarkers such as novel components of the microbiome, non-coding RNAs, extracellular vesicles and circulating tumor DNA are extensively being researched for their role in CRC management. Majority of these components have shown promising results on their clinical application in CRC including early detection, observe tumor heterogeneity for treatment and response, prediction of metastases and relapse and detection of minimal residual disease. Therefore, in this review, we aim to provide updated information on various novel liquid biopsy markers such as a) oral microbiota related bacterial network b) gut microbiome-associated serum metabolites c) PIWI-interacting RNAs (piRNAs), microRNA(miRNAs), Long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and d) circulating tumor DNAs (ctDNA) and circulating tumor cells (CTC) for their role in disease diagnosis, prognosis, treatment monitoring and their applicability for personalized management of CRC.