Gastric microbiome profile throughout gastric carcinogenesis: beyond helicobacter

Autores da FMUP

• Pedro Filipe Vieira Pimentel Nunes

  Autor

• António Sousa Barros

  Autor

• Isabel Alexandra Marcos Miranda

  Autor

• Glória De Fátima Almeida Conceição

  Autor

• Marta Borges Canha

  Autor

• Joaquim Adelino Correia Ferreira Leite Moreira

  Autor

• Diogo Miguel Pereira Libânio Monteiro

  Autor

• Mário Jorge Dinis Ribeiro

  Autor

Participantes de fora da FMUP

• Pita, I

Unidades de investigação

• Cirurgia e Fisiologia

• Laboratório Associado RISE- Rede de Investigação em Saúde

  

  Investigador

  Fernando Carlos De Landér Schmitt

• Medicina da Comunidade, Informação e Decisão em Saúde

• RISE-Health

  

  Investigador

  Fernando Carlos De Landér Schmitt

Abstract

Background Gastric dysbiosis has been hinted as a potential cause of gastric cancer. However, changes in microbiome throughout the major stages of gastric carcinogenesis remain mostly unknown. Objective To describe gastric microbiome at different stages, analysing for the first time dysbiosis specifically in patients with early gastric cancer (EGC). Methods Cross-sectional study including patients (n = 77) with endoscopically and histologically confirmed normal stomachs (controls; n = 25), advanced atrophic gastritis with intestinal metaplasia (IM; n = 18) and EGC (n = 34). Endoscopic biopsies from antrum and corpus (n = 154) were analyzed. Next-generation sequencing was performed characterizing microbial communities down to the species level based on full-length 16SrRNA gene profiling. Results Significant differences were found in the microbiome profile between the groups. Firmicutes were more frequent (p = .012) and Proteobacteria were less frequent (p = .04) both in the IM and EGC when comparing to controls. Relative frequency of Helicobacter pylori, when present, was much higher in the controls (83%) when comparing to the other groups (IM 1%, EGC 27%; p = .006), being the dominant bacteria only in the controls. Dysbiosis was present already and more significantly at the IM stage, with two bacteria progressively increasing from controls to IM then to cancer: Gemella from 1.48 to 3.9% (p = .014); and Streptococcus from 19.3 to 33.7% (p = .04), being the EGC dominant bacteria. Conclusions Our results confirm Helicobacter pylori dominancy in non-atrophic stomachs and progressive dysbiosis throughout gastric carcinogenesis. Gemella but particularly Streptococcus is significantly increased in patients with EGC. Specific modulation of these bacteria may change gastric cancer risk.

Keywords

• Gastric cancer; microbiome; intestinal metaplasia; Helicobacter; Streptococcus