Therapeutic potential of cytokine and chemokine antagonists in cancer therapy

A new paradigm is becoming widely accepted, that chronic inflammation, driven in part by chemokines and cytokines at the site of a tumour, may facilitate tumour progression instead of promoting anti-tumour immunity. Tumours and activated stromal cells secrete pro-inflammatory chemokines and cytokines that act either directly or indirectly through stimulation of the vascular endothelium to recruit leukocytes to the tumour. After activation, these tumour-associated leukocytes release angiogenic factors, mitogens, proteolytic enzymes, and chemotactic factors, recruiting more inflammatory cells and stimulating angiogenesis to sustain tumour growth and facilitate tumour metastasis. Breaking this cycle by inhibiting targets such as cytokines, chemokines and other inflammatory mediators, either alone, or more realistically, in combination with other therapies, such as anti-angiogenic or cytotoxic agents, may provide highly efficacious therapeutic regimens for the treatment of malignancies. This article reviews anti-cytokine and anti-chemokine therapies being pursued in cancer, and discusses in more detail anti-tumour necrosis factor-α (TNF) approaches.