FN1 and colorectal cancer: Colorectal cancer can be diagnosed by Lachnoclostridium as a marker:(1) Metagenomic analysis identified “m3” from a Lachnoclostridium sp., Fusobacterium nucleatum (Fn), and Clostridium hathewayi (Ch) to be significantly enriched in CRC.(2) The combination of m3 with Fn, Ch, Bacteroides, and FIT can diagnose CRC most accurately.