Purpose: To analyze the lymph node metastasis status and prognosis in CRCs and to investigate the gut microorganisms and microbial metabolites at different lymph node stages.
Methods: The Surveillance, Epidemiology, and End Results (SEER) database and STAT software were used to analyze the clinical features and lymph node metastasis. Bacterial 16S V3-V4 and fungal ITS V3-V4 ribosomal RNA genes were sequenced in 53 stool samples and gas chromatography/mass spectrometry (GS/MS) was performed to detect the microbial metabolites in 48 stool samples from CRC patients.
Results: A higher number of lymph node metastases predicted a poor prognosis. Inadequate evaluation of lymph nodes affects the accuracy of prognostic assessments. We constructed a nomogram model for the assessment of prognostic factors. There were multiple characteristic bacteria identified, including Akkermansia, Megamonas, Dialister , etc., and fungi, including Penicillium, Filobasidium, Debaryomyces , etc. A total of 27 characteristic microbial metabolites in different lymph node metastasis status were also identified.
Conclusion: Gut microorganisms and microbial metabolites may provide reference and guidance for the adequate lymph node assessments (ALNA) in CRC.
Keywords: microbiome, metabolites, lymph node, metastasis, colorectal cancer