A study found that changes in gut bacteria and their metabolites may play an important role in rectal adenocarcinoma (READ). Researchers compared stool samples from 33 patients with rectal cancer and 34 healthy individuals and identified major differences in gut microbiota and metabolic activity.
One key finding was that guanidinoacetic acid (GAA), a metabolite involved in creatine production, was significantly higher in cancer patients. Levels of GAA dropped in patients who responded well to treatment, suggesting it may also reflect therapy response. Higher GAA levels were linked to specific bacteria such as Peptostreptococcus.
Laboratory tests showed that GAA can directly promote cancer behavior by increasing tumor cell growth, spread, and survival while reducing cell death. It also interacted with several human proteins that may drive cancer progression.
Overall, the study suggests that gut bacteria–driven changes in GAA levels may contribute to rectal cancer development and could serve as both a biomarker and a potential treatment target.