Abstract
Simple SummarySpecific guidance regarding cancer treatment in coronavirus disease-19 (COVID-19) patients is lacking due to minimal knowledge. It has been observed that patients with severe COVID-19 develop a dysbiotic microbiota of the gut. This impact may be long-lasting, resulting in a greater possibility of a future diagnosis of colorectal cancer (CRC) or aggravating the condition in those already afflicted. Given that CRC is the third most common and third deadliest type of cancer, we must understand how infection with SARS-CoV-2 will impact CRC biology and treatment strategies.The emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), in December 2019 led to a worldwide pandemic with over 170 million confirmed infections and over 3.5 million deaths (as of May 2021). Early studies have shown higher mortality rates from SARS-CoV-2 infection in cancer patients than individuals without cancer. Herein, we review the evidence that the gut microbiota plays a crucial role in health and has been linked to the development of colorectal cancer (CRC). Investigations have shown that SARS-CoV-2 infection causes changes to the gut microbiota, including an overall decline in microbial diversity, enrichment of opportunistic pathogens such as Fusobacterium nucleatum bacteremia, and depletion of beneficial commensals, such as the butyrate-producing bacteria. Further, these changes lead to increased colonic inflammation, which leads to gut barrier disruption, expression of genes governing CRC tumorigenesis, and tumor immunosuppression, thus further exacerbating CRC progression. Additionally, a long-lasting impact of SARS-CoV-2 on gut dysbiosis might result in a greater possibility of new CRC diagnosis or aggravating the condition in those already afflicted. Herein, we review the evidence relating to the current understanding of how infection with SARS-CoV-2 impacts the gut microbiota and the effects this will have on CRC carcinogenesis and progression.
Highlights
The gut microbiota plays a crucial role in health through its protective, trophic, and metabolic activities
The results indicate that dysbiosis ococcurred in COVID-19 patients, and changes in the gut microbial community were curred in COVID-19 patients, and changes in the gut microbial community were associated associated with disease severity and hematological parameters
The SARS-CoV-2 pandemic has left many unanswered questions on the long-term impacts of this virus post-infection. This question is of particular importance to those with underlying comorbidities before the onset of COVID-19
Summary
Infection with a respiratory syncytial virus (RSV), along with other family members of Coronaviridae, has been shown to inhibit and degrade p53, a tumor suppressor that can inhibit carcinogenesis [12,13] This leads to the question, are cancer patients more likely to develop lethal complications after being infected by SARS-CoV-2? A dysbiotic gut microbiota is incapable of properly signaling to distal tissues though bacterial metabolic by-products This is further augmented alongside viral infections, which increase systemic inflammation, resulting in further dysbiosis to the symbiotic microbiome within the host [25]. It has been hypothesized that the antiviral CD8+ T cell immunity induced by SARS-CoV-2 infections could be used to enhance cancer immunotherapies [29] While these studies provide the foundational premise for the impact of SARS-CoV-2, further understanding of how respiratory viral infections, SARS-CoV-2, affect CRC progression represents a knowledge gap and critical unmet need. A detailed understanding of how SARS-CoV-2 infection impacts the gut microbiota and CRC progression is of utmost importance [30]
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