Butyricicoccus could also downregulate the expression of PLAC8, which may be associated with CRC recurrence, and induce apoptosis in PLAC8-overexpressing cells (49). Therefore, we speculated that the reduction of Butyricicoccus is one of the diagnostic markers of colorectal cancer metastasis, and our experimental results showed that Butyricicoccus in CRC with metastasis was less abundant than that in CRC without metastasis, which supported this speculation. This evidence concerns the gene PLAC8 and colorectal cancer.