Abstract PS16-35: Microbiota and breast cancer in mexican women
Authors: Valdés Arely Berenice González , Rocha Juan Enrique Bargallo , Castro Juan Manuel Medina , Plasencia Carlos Pérez , Catalan Oliver Millan , Pérez Elvia Fernández , Martinez Antonio Daniel , De León David Cantú 
Published: February 2021

Microbiota and breast cancer in Mexican womenStudy Type: ObservationalTime Perspective: Cross-SectionalThe human microbiome refers to the genes of the universe of microbes that inhabit our skinand mucosal surfaces. Epidemiological studies implicated that human microfloracontributes to 16% more of malignant neoplasms worldwide, either as a risk factor orcausative agent.Although hereditary and genetic factors represent 5% to 10% of breast cancer cases, 70%of them are due to a host of environmental factors. Migrant studies demonstrated that non-hereditary factors are the main drivers of international and inter-ethnic differences in theincidence and mortality of breast cancer. The environment contributes to the developmentof the disease; although, the factors involved are not well known, among the latter is theinfluence of microorganisms and, therefore, attention is recently being paid to themammary microbiota. This study hypothesizes that women with breast cancer havedifferences in the composition and functionality of breast microbiota compared to womenwithout breast disease.Inclusion and exclusion criteria. Women's age range of 25-70 years. Women with confirmedbreast cancer diagnosis scheduled for surgery as primary treatment (mastectomy orconservative surgery) surgically intervened with breast augmentation or reduction withoutbreast cancer and signed informed consent. Women with antecedents of cancer, or whohave received antibiotic treatment one month before recruitment, or any neoadjuvanttherapy, without breast surgery in the past for any reason. Immunocompromised patients.Pregnant patients or with the use of implants were excluded from the study.Sample size. Sixty women with confirmed breast cancer matched with 30 women withoutcancer, and 30 with benign breast disease. Three hospitals participated in the recruitment:Instituto Nacional de Cancerología, Centro Oncológico Estatal ISSEMYM and Centromedico ABC.Method: DNA total of tissue samples was extracted using the Quick-DNA Miniprep Plus Kit(Zymo research Cat. D4068). 5 uL of DNA isolated of tissue samples were amplified with16S™ Metagenomics Kit (Thermo Fisher Scientific, Cat. A26216) and were marked with IonXpress Barcode Adapter (Thermo Fisher Scientific cat. no. 4471250), purified with AMPureXP reagent (Beckman Coulter cat. no. A63881) and quantified with Ion Universal LibraryQuantitation Kit (Thermo Fisher Scientific cat. no. A26217). After that, emulsion PCR wasprepared in the Ion OneTouch 2 System (Thermo Fisher Scientific). For sequencing, we usedthe Ion PGM Hi-Q view Sequencing kit (REFA30044) with chips 318 in the Ion torrent PGMinstrument (Thermo Fisher Scientific).

Results: In this study, we employed 16s rRNA sequencing to analyze the bacterial profiles ofnormal, benign, and breast tumor tissues. We observed that the beta diversity between thethree types of tissues is similar, although patients showed significant differences in theabundance of specific bacteria genera depending on the tissue of origin. We determinedthat bacteria from the genera Burkholderia had a lower relative abundance in benign tissuesthan normal tissues, although these genera had a higher relative abundance in tumortissues. We found a more significant difference in the amount of bacteria between benignand tumoral tissues; we observed that the seven genera (Aeromonas, Alcanivorax, Burkholderia, Corynebacterium, Finegoldia, Pseudomonas and Staphylococcus) are greaterintumortissueswhereasfivegenera: Cupriavidus, Microbacterium, Ralstonia, Renibacterium and Sphingomonas had alower relative abundance in tumoral tissues. This study suggests that bacterial beta-diversity does not change much among the analyzed tissues; however, it is specific bacterialgenera that change their relative abundance during tumor progression.

Citation Format: Arely Berenice González Valdés, Juan Enrique Bargallo Rocha, Juan Manuel Medina Castro, Carlos Pérez Plasencia, Oliver Millan Catalan, Elvia Fernández Pérez, Antonio Daniel Martinez, David Cantú De León. Microbiota and breast cancer in mexican women [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS16-35.