To investigate the above hypothesis, we performed high-throughput profiling of the mucin phenotypes and bacterial communities present in 108 gastric adenocarcinoma and 20 functional dyspepsia (FD) (i.e., for comparison) cases using validated mucin-based RT-qPCRs with subsequent immunohistochemistry (IHC) validation and 16S rRNA gene sequencing integrated with clinical data to identify mucin-microbiota signatures associated with GC and clinical outcome. Here, MUC5AC is linked to gastric adenocarcinoma.