We discovered that A. muciniphila effectively upregulated the KLF4 mRNA level (the goblet cell differentiation marker) and MUC2 expression while not affecting the HES1 mRNA level (the absorptive epithelial cell differentiation indicator) using colorectal cancer cell lines HT−29, LS174T, and Caco2 (Figure 1A−D and Figure S3A). The gene discussed is HES1; the disease is colorectal cancer.