Cancer and the microbiome: potential applications as new tumor biomarker

Abstract

Microbial communities that colonize in humans are collectively described as microbiome. According to conservative estimates, about 15% of all types of neoplasms are related to different infective agents. However, current knowledge is not sufficient to explain how the microbiome contributes to the growth and development of cancers. Large and thorough studies involving colonized, diverse and complex microbiome entities are required to identify microbiome as a potential cancer marker and to understand how the immune system is involved in response to pathogens. This article reviews the existing evidence supporting the enigmatic association of transformed microbiome with the development of cancer through the immunological modification. Ascertaining the connection between microbiome and immunological responses with risk of cancer may direct to explaining significant advances in the etiology of cancer, potentially disclosing a novel paradigm of research for the management and prevention of cancer.

Keywords:

• cancer biomarker
• cancer diagnosis
• cancer prevention
• immunological modification
• transformed microbiome

Acknowledgements

The authors are thankful to C Zaharie, Scientific Expert Status, Health Canada Scientific Experts Database, Ottawa, Canada, for critical review and valuable suggestions for improving the quality of this manuscript.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Normal human microbiome may prevent various diseases, including cancer, whereas alterations in the normal microbiome creating a transformed microbiome may predispose the individual to numerous conditions, man of them related to cancer.

• The association between microbiota and the host immune system may result in a cause of inflammation and development or progression of cancer.

• Most of the available evidences are still to be validated and confirmed.

• A routine search for specific pro-oncogenic pathogens in all patients diagnosed with certain cancer types within a multidisciplinary, multicenter and multinational setting would definitely boost this research field.

• Further development of new high-throughput sequencing techniques is warranted to facilitate a molecular characterization of different neoplasms and their respective potentially causal pathogens.