@article{2980669,
    title = "Gut microbiota in lung cancer: Where do we stand?",
    author = "Georgiou, K. and Marinov, B. and Farooqi, A.A. and Gazouli, M.",
    journal = "International Journal of Molecular Sciences",
    year = "2021",
    volume = "22",
    number = "19",
    publisher = "MDPI",
    issn = "1422-0067",
    doi = "10.3390/ijms221910429",
    keywords = "immune checkpoint inhibitor, cancer chemotherapy;  cancer growth;  drug efficacy;  drug metabolism;  human;  immune response;  immunomodulation;  intestine flora;  lung cancer;  lung carcinogenesis;  lung microbiota;  lymphocyte differentiation;  nonhuman;  regulatory T lymphocyte;  Review;  treatment response;  drug therapy;  immunology;  intestine flora;  lung tumor;  microbiology;  non small cell lung cancer;  pathology, Carcinoma, Non-Small-Cell Lung;  Gastrointestinal Microbiome;  Humans;  Immune Checkpoint Inhibitors;  Lung Neoplasms;  T-Lymphocytes, Regulatory",
    abstract = "The gut microbiota (GM) is considered to constitute a powerful “organ” capable of influencing the majority of the metabolic, nutritional, physiological, and immunological processes of the human body. To date, five microbial-mediated mechanisms have been revealed that either endorse or inhibit tumorigenesis. Although the gastrointestinal and respiratory tracts are distant physically, they have common embryonic origin and similarity in structure. The lung microbiota is far less understood, and it is suggested that the crosslink between the human microbiome and lung cancer is a complex, multifactorial relationship. Several pathways linking their respective microbiota have reinforced the existence of a gut–lung axis (GLA). Regarding implications of specific GM in lung cancer therapy, a few studies showed that the GM considerably affects immune checkpoint inhibitor (ICI) therapy by altering the differentiation of regulatory T cells and thus resulting in changes in immunomodulation mechanisms, as discovered by assessing drug metabolism directly and by assessing the host immune modulation response. Additionally, the GM may increase the efficacy of chemotherapeutic treatment in lung cancer. The mechanism underlying the role of the GLA in the pathogenesis and progression of lung cancer and its capability for diagnosis, manipulation, and treatment need to be further explored. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)."
}