56 AI-2 could induce IL-8 expression in HCT-8 colon cancer cells.54 The autoinducing peptides (AIPs) synthesized by human microbiota were found to influence mammalian cells, promoting metastasis of cancer cells57,60 and penetrate the blood-brain barrier.57 Although the specific mechanism(s) through which AIs influence mammalian cells is unclear, modified immune responses by AIs unravel another circuit of how pathogens establish an infection.107. The gene discussed is CXCL8; the disease is malignant colon neoplasm.