Characterization of the gut microbiome in premalignant colon lesions from Chilean patients

Colorectal cancer (CRC) is the third most diagnosed cancer globally and a leading cause of cancer-related mortality. The disease typically progresses over time from benign precursor lesions known as adenoma. Recent studies highlight the pivotal role of the gut microbiota in colorectal carcinogenesis, suggesting a complex interplay between microbial communities and tumor development. This study investigates the gut microbiota profiles of a series of cases from a single center, including Chilean individuals with and without adenomas, using 16S rRNA sequencing to interrogate microbial changes that may be associated with the transition from a healthy colon epithelium to precancerous lesions. The results revealed that alpha and beta diversity metrics showed no significant differences. Patients with precancerous lesions exhibited an increase in the Prevotella, Fusobacterium, and Desulfovibrio genera, all of which are bacteria associated with inflammation and intestinal dysbiosis. In addition, a microbial signature is associated with adenomas, characterized by an increased abundance of Proteobacteria and a decreased abundance of Firmicutes compared to healthy controls. Notably, Succinivibrio dextrinosolvens was exclusively identified and significantly increased in patients with any type of polyps, suggesting its potential role as a biomarker of dysbiosis and CRC progression. These findings provide a baseline for understanding the microbial landscape in our population, underscoring specific microbial markers associated with premalignant lesions, which highlight the potential of microbiome analysis as a predictive and diagnostic tool for colorectal diseases.