Microbiota Profiles of Cancer Tissue, Normal Mucosal Tissue, and Feces in Colorectal Cancer at Wahidin Sudirohusodo Hospital

<ns3:p> Introduction Colorectal cancer (CRC) is a major global health concern. Gut microbiota dysbiosis has been implicated in CRC development by influencing inflammation, immune responses, and metabolic pathways. This study aimed to compare microbiota composition in cancerous tissue, adjacent normal mucosa, and feces from CRC patients. Methods A descriptive cross-sectional study was performed with 20 CRC patients. Tumor tissue, normal mucosa, and fecal samples were collected and analyzed using PCR and sequencing to identify bacterial taxa. The prevalence of species, genera, phyla, and functional groups (proteolytic <ns3:italic>vs.</ns3:italic> saccharolytic) was compared across sample types. Results Participants were evenly distributed by age and gender, and most had tumors in the rectosigmoid region. <ns3:italic>Escherichia coli</ns3:italic> was the most frequently detected species in tumor tissue (40%), normal mucosa (30%), and feces (30%). Additional bacteria, including <ns3:italic>Bacteroides fragilis</ns3:italic> , <ns3:italic>Shigella</ns3:italic> sp., <ns3:italic>Salmonella enterica</ns3:italic> , <ns3:italic>Pseudomonas</ns3:italic> sp., <ns3:italic>Bacteroides graminisolvens</ns3:italic> , and <ns3:italic>Aeromonas</ns3:italic> sp., appeared in tumor tissues. At the genus level, <ns3:italic>Escherichia</ns3:italic> dominated all samples. At the phylum level, <ns3:italic>Proteobacteria</ns3:italic> was highest in tumor (65%), normal mucosa (60%), and fecal samples (60%). Proteolytic microbiota were more common than saccharolytic microbiota in all sample types. Conclusions CRC patients display distinct microbiota patterns with increased pro-inflammatory and potentially pathogenic bacteria, especially <ns3:italic>E. coli</ns3:italic> and <ns3:italic>Proteobacteria.</ns3:italic> Predominance of proteolytic microbes and reduced saccharolytic populations indicates metabolic shifts that may contribute to carcinogenesis. These findings suggest microbiota profiles could serve as biomarkers for CRC. Larger, more comprehensive studies are recommended. </ns3:p>