LAUSR

BACKGROUND & AIMS Enteric mycobiota is a major component of human gut microbiota, but its role in colorectal cancer (CRC) remains largely elusive. We conducted a meta-analysis to uncover the contribution of fungal mycobiota to CRC. METHODS We retrieved fecal metagenomic datasets from 7 previous publications and established an additional in-house cohort, totaling 1,329 metagenomes (454 CRC, 350 adenoma and 525 healthy subjects). Analyses of mycobiota composition and microbial interactions were conducted. Candidate CRC-enriched fungal species (Aspergillus rambellii) was functionally validated in vitro and in vivo. RESULTS Multi-cohort analysis revealed that the enteric mycobiota was altered in CRC. We identified fungi that were associated with CRC and adenoma patients from multiple cohorts. Signature CRC-associated fungi included 6 enriched (Aspergillus rambellii, Cordyceps sp. RAO-2017, Erysiphe pulchra, Moniliophthora perniciosa, Sphaerulina musiva, and Phytophthora capsici) and 1 depleted species (Aspergillus kawachii). Co-occurrent interactions among CRC-enriched fungi became stronger in CRC compared to adenoma and healthy subjects. Moreover, we reported the trans-kingdom interactions between enteric fungi and bacteria in CRC progression, of which A. rambellii was closely associated with CRC-enriched bacteria Fusobacterium nucleatum. A. rambellii promoted CRC cell growth in vitro and tumor growth in xenograft mice. We further identified that combined fungal and bacterial biomarkers were more accurate than panels with pure bacterial species to discriminate CRC patients from healthy subjects (AUC relative change increased by 1.44%-10.60%). CONCLUSIONS This study reveals enteric mycobiota signatures and pathogenic fungi in stages of colorectal tumorigenesis. Fecal fungi can be utilized, in addition to bacteria, for non-invasive diagnosis of CRC patients.