Inflammation and Inflammatory Cytokine Contribute to the Initiation and Development of Ulcerative Colitis and Its Associated Cancer

Dysregulated inflammatory responses play a pivotal role in the initiation, development, and progression of tumors, as demonstrated by the association between ulcerative colitis and the increased risk of colon carcinoma. In this review, the underlying mechanisms for the initiation and development of ulcerative colitis and colitis-associated cancer are described, mainly focusing on the inflammation and inflammatory cytokine. Disruption of the intestinal mucosal barrier and bacterial invasion resulted in intestinal inflammation; and further TLR4/NF-κB stimulation in intestinal epithelial cells, inflammatory cell infiltration, and inflammatory cytokine release all confer survival advantages to or promote abnormal proliferation in susceptible cells. Importantly, the respective roles of TLR4/NF-κB, TNF-α, and IL-6 in intestinal epithelial cells and inflammatory cells are summarized in detail. A thorough understanding of these molecular mechanisms may help researchers and clinicians to explore novel approaches for the prevention and treatment of colitis-associated cancer.