TNF and Arthritis: Previous studies found that up-regulated nuclear factor kappa B (NF-kB), induced by 5-FU in the intestine, was able to enhance the expression of 5-FU-affected genes, [23] meanwhile activation of NF-kB have been observed in several inflammatory diseases, such as inflammatory bowel diseases (IBDs), glomerulonephritis and local joint inflammation, [24] besides multiple inflammatory cytokines, especially tumor necrosis factor (TNF), can induce TJs disruption.