Characterization of the resident and transient gastric microbiota in patients with gastric adenocarcinoma

• Grant number: 18/14267-2
• Support type: Scholarships in Brazil - Master
• Effective date (Start): November 01, 2018
• Effective date (End): December 31, 2020
• Field of knowledge: Biological Sciences - Genetics - Human and Medical Genetics
• Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal researcher: Emmanuel Dias-Neto
• Grantee: Gabriela Estrela de Albuquerque
• Home Institution: A C Camargo Cancer Center. Fundação Antonio Prudente (FAP). São Paulo , SP, Brazil
• Associated research grant: 14/26897-0 - Epidemiology and genomics of gastric adenocarcinomas in Brazil, AP.TEM

Abstract

Gastric Adenocarcinoma accounts for about 95% of all cases of gastric cancer, and is among the most common neoplasms in the world, with a high incidence and mortality. Among the classic treatments with curative surgery, we highlight the surgery, which is usually preceded by chemotherapy to reduce the tumor mass. Several recent studies have demonstrated that the microbiota actively participates in the outcome of chemotherapy, either through the activation or inactivation of drugs, as well as in the immunomodulation of the patient's response to the treatment, and can perform a positive or negative improvement. Despite the importance of the gastric microbiota, most studies are restricted to the H. pylori bacterium and the Epstein Bar virus, and little has been found on the microbiota that actually resides in the stomach and should have a greater relation with Gastric Adenocarcinoma compared to that which is transient, derived from anterior portions of the upper aero digestive tract. In view of this, the main objective of this study is the generations of evidence to suggest which microorganisms are alive and reside in the gastric cavity, in contrast to those whose nucleic acids are found to be free, with no evidence of presence or metabolic activity at this site. For this, we will use biopsies and gastric juice from patients with Gastric Adenocarcinoma that will be analyzed by metagenomic shotgun, 16S and metatranscriptomic studies with RNAseq. The results, using DNA and RNA of higher or lower molecular weight, as well as data from biopsies, gastric juice and saliva will be contrasted and used as evidence of the activity status of the bacterial populations, indicating which microorganisms are most likely to be alive and active in patients with Gastric Adenocarcinoma. Thus, we hope to contribute to a better understanding of the impact of the stomach microbiota and its role in gastric cancer.