Human microbiota and breast cancer: is there any relevant link? A literature review and new horizons toward personalised medicine

• Autor(a) principal: Costa, Diogo Alpuim
• Data de Publicação: 2021
• Outros Autores: Nobre, José Guilherme, Batista, Marta Vaz, Ribeiro, Catarina, Calle, Catarina, Cortes, Alfonso, Marhold, Maximilian, Negreiros, Ida, Borralho, Paula, Brito, Miguel, Cortes, Javier, Braga, Sofia Azambuja, Costa, Luís
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.21/12964
• topic: Breast cancer; Microbiota; Microbiome; Dysbiosis; Metabolomics; Pharmacomicrobiomics; Personalized medicine; Review

Breast cancer (BC) is the most common malignancy and the second cause of cancer-specific death in women from high-income countries. Recently, gut microbiota dysbiosis emerged as a key player that may directly and/or indirectly influence the development, treatment, and prognosis of BC through diverse biological processes: host cell proliferation and death, immune system function, chronic inflammation, oncogenic signaling, hormonal and detoxification pathways. Gut colonization occurs during the prenatal period and is later diversified over distinct phases throughout life. In newly diagnosed postmenopausal BC patients, an altered fecal microbiota composition has been observed compared with healthy controls. Particularly, β-glucuronidase bacteria seem to modulate the enterohepatic circulation of estrogens and their resorption, increasing the risk of hormone-dependent BC. Moreover, active phytoestrogens, short-chain fatty acids, lithocholic acid, and cadaverine have been identified as bacterial metabolites influencing the risk and prognosis of BC. As in the gut, links are also being made with local microbiota of tumoural and healthy breast tissues. In breast microbiota, different microbial signatures have been reported, with distinct patterns per stage and biological subtype. Total bacterial DNA load was lower in tumor tissue and advanced-stage BC when compared with healthy tissue and early-stage BC, respectively. Hypothetically, these findings reflect local dysbiosis, potentially creating an environment that favors breast tumor carcinogenesis (oncogenic trigger), or the natural selection of microorganisms adapted to a specific microenvironment. In this review, we discuss the origin, composition, and dynamic evolution of human microbiota, the links between gut/breast microbiota and BC, and explore the potential implications of metabolomics and pharmacomicrobiomics that might impact BC development and treatment choices toward more personalized medicine. Finally, we put in perspective the potential limitations and biases regarding the current microbiota research and provide new horizons for stronger accurate translational and clinical studies that are needed to better elucidate the complex network of interactions between host, microorganisms, and drugs in the field of BC.