As can be seen from the species correlation network plot (Fig. 8a), the abundance of Lachnospiraceae with high expression in the CRC + Fn group was negatively correlated with Muribaculaceae, Prevotellaceae_NK3B31_group, and [Eubacterium]_coprostanoligenes_group, which had higher expression in the control group, and was positively correlated with the abundance of Lachnospiraceae_NK4A136_group with high expression in the CRC + Fn group and Rikenellaceae_RC9_gut_group with high expression in CRC + Fn + Cys group. Here, FN1 is linked to colorectal carcinoma.