The constitutive expression of angiogenic and tumorigenic chemokines by tumour cells facilitates the growth of tumours. The transcription of these angiogenic and tumorigenic chemokine genes is modulated, in part, by the nuclear factor-κB (NF-κB) family of transcription factors. In some tumours, there is constitutive activation of the kinases that modulate the activity of inhibitor of NF-κB (IκB) kinase (IKK), which leads to the constitutive activation of members of the NF-κB family. This activation of NF-κB is associated with the dysregulation of transcription of genes that encode cytokines, chemokines, adhesion factors and inhibitors of apoptosis. In this review, I discuss the factors that lie upstream of the NF-κB cascade that are activated during tumorigenesis and the role of the putative NF-κB enhanceosome in constitutive chemokine gene transcription during tumorigenesis.Chemokines are small, pro-inflammatory peptides; they are often expressed in response to the induction of expression of nuclear factor-κB (NF-κB) by cytokines or other stimuli. Chemokines regulate the transport, activation and, sometimes, proliferation of several cell types, including myeloid, lymphoid, endothelial and epithelial cells 1,2 . There are four chemokine subfamilies -CXC, C, CX 3 C and CC -based on the positions of conserved cysteine residues near the amino terminus of the proteins 1 (TABLE 1). Melanoma growthstimulatory activity (CXCL1) and interleukin-8 (IL-8, CXCL8) are members of the CXCchemokine family, which also includes interferon-γ (IFN-γ)-inducible gene 10 (CXCL10), IFN-inducible T-cell α-chemoattractant (CXCL11), monocyte induced by IFN-γ (CXCL9), epithelial-derived neutrophil-activating peptide 78 (ENA-78, CXCL5), granulocyte chemotactic protein 2 (CXCL6), neutrophil activating peptide 2 (CXCL7), a mitogen for Bcell progenitors known as stromal-derived factor (CXCL12) and B-cell-activating factor 1/Blymphocyte chemoattractant (BCA1/BLC, CXCL13) 1 . The expression of various members of the chemokine superfamily is induced by several cytokines, such as IL-1 and tumour-necrosis factor (TNF), through an NF-κB-mediated event; by IFN-γ through the Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathway; or by activating protein 1 (AP1)-mediated transcription. The transcription of chemokine genes is often inhibited by transforming growth factor-β (TGF-β) and glucocorticoids 1 .As the CXC-chemokines CXCL1 and CXCL8 have been associated with tumour growth, metastasis and angiogenesis, I concentrate on these important chemokines. The biological functions of chemokines are mediated through seven-transmembrane G-protein-coupled receptors. CXCL8 and CXCL6 bind to the chemokine receptors CXCR1 and CXCR2, whereas CXCL1 and other CXC-chemokines that have a Glu-Leu-Arg (ELR) motif at their amino terminus (CXCL2, -3 and-5) bind to and activate CXCR2 only 2 . There are also viral receptors Both the CXC-chemokines and their receptors, and the CC-chemokines and their receptors, are involved in ...