TLR4 and colorectal cancer: nucleatum can induce colorectal cancer cell proliferation and migration, through activation of the toll-like receptor 4 (TLR4)/myeloid differentiation primary response gene 88 (MYD88)/NF-κB signaling pathway in tumor cells, increasing the expression of microRNA-21 (miR-21), thereby inhibiting RAS protein activator like 1 (RASA1), and activating the inherent RAS signaling of tumors, resulting in elevated transcription of genes related to growth and proliferation.