The Relationship Between the Gut-Microbiome and Colorectal Cancer

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Clinical Trials

Animal/Mouse trials

Negative Associations

Future hopes

Studies have shown that people with colorectal cancer have an altered gut microbiome compared to healthy individuals, with a decrease in the diversity of gut microbes and an increase in potentially harmful bacteria. (Sánchez-Alcoholado et al., 2020)

These changes in the gut microbiome have been associated with chronic inflammation, which can promote the development and progression of colorectal cancer. (Sánchez-Alcoholado et al., 2020)

Functions of the gut microbiome

The gut microbiome has three primary roles: structural, protective, and metabolic. It plays a crucial part in various processes such as nutrient and mineral absorption, the synthesis of enzymes, vitamins, and amino acids, as well as the production of short-chain fatty acids (SCFAs). (Rebersek, 2021)

Over the past few years, the importance of the microbiome in CRC has been increasingly emphasized, particularly in terms of how the gut microbiome can cause initial inflammation and affect various signaling pathways that promote carcinogenesis. Compared to a healthy gut microbiome, the microbiota in CRC patients consists of different strains of bacteria, including Bacteroides fragilis, Streptococcus gallolyticus, Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Parvimonas, Peptostreptococcus, Porphyromonas, and Prevotella, which have been linked to CRC development. (Rebersek, 2021).

Higher amounts of these bacterial strains in fecal and tumor samples from CRC patients can be used as biomarkers for CRC. The gut microbiota can influence colorectal carcinogenesis through various mechanisms, including inflammation, immune response regulation, and altered metabolism of dietary components, which can also lead to the production of harmful microbial-derived products like metabolites or genotoxins.(Rebersek, 2021).

Studies using mouse models with a genetic predisposition to colorectal cancer have demonstrated that the microbiota can trigger protumorigenic responses. (Sánchez-Alcoholado et al., 2020)

For example, Li et al. found that the gut microbiota can accelerate tumor growth in APC (Min/+) mice by activating the c-Jun/JNK and STAT3 signaling pathways, in addition to causing anemia. (Sánchez-Alcoholado et al., 2020)

In contrast, research has shown that in IL-10 deficient mice, an increased microbiota-specific Th1 response worsened colitis, leading to the formation of adenocarcinoma. (Sánchez-Alcoholado et al., 2020)

Furthermore, in germ-free mice, the transfer of stool from CRC patients increased intestinal cell proliferation, suggesting that the microbiota can promote tumor formation. (Sánchez-Alcoholado et al., 2020)

Precision medicine in the present day requires a personalized approach to probiotics, as opposed to a one-size-fits-all approach. This shift is crucial in understanding the clinical implications of the gut microbiome in CRC prevention, systemic treatment planning, and the reduction of treatment-related side effects. (Rebersek, 2021)

clinical research should consider factors such as geography, race, sex, and diet, as well as the impact of cancer treatments like chemotherapy and immunotherapy on the microbiome. (Rebersek, 2021)

Each individual's unique microbiome from birth necessitates patient-tailored personalized medicine, which can be aided by artificial intelligence and machine learning for optimal results. (Rebersek, 2021)

Additionally, it is important to note that promoting a healthy gut microbiome can have a positive impact on overall health, ultimately benefiting society as a whole. (Rebersek, 2021)

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A study conducted in 2019 found that patients with Colorectal Cancer should be taking a prebiotic as they improved the abundance of four commensal microbiota containing opportunistic pathogens in patients with CRC (Xie et al., 2019).

A study by (Aslam et al., 2020), showed that the colonic microbial community changed noticeably after an Aquamin (calcium-, magnesium-, and multiple trace element–rich natural product) treatment.

There are many feasibility studies completed in regard to research surrounding the gut microbiome and colorectal cancer

A study conducted by Prizment et al. (2020) concluded that Several microbial taxa (including Rubinococcaceae, Clostridium XlVa, Parabacteroides, and Dorea) were affected by aspirin intake in a way that was compatible with an earlier hypothesis based on their relationship with CRC. This shows that aspirin may affect the development of CRC through altering the microbiome in the gut.