GAL and cancer: Cancerous tissue is targeted by F. nucleatum via an interaction between the Fusobacterium lectin Fap2 and the tumor-specific surface Gal-Gal NAc. This attachment elicits the expression of MUC2 and TNF-α in colon cancer cells. F. nucleatum is one of the strains that is enriched in the gastric cancer microbiota, and considering its significance in colorectal cancer, F. nucleatum could also play a pivotal role in the development of gastric cancer.