Nuclear factor κB (NF-κB) transcription factors have a key role in many physiological processes such as innate and adaptive immune responses, cell proliferation, cell death, and inflammation. It has become clear that aberrant regulation of NF-κB and the signalling pathways that control its activity are involved in cancer development and progression, as well as in resistance to chemotherapy and radiotherapy. This article discusses recent evidence from cancer genetics and cancer genome studies that support the involvement of NF-κB in human cancer, particularly in multiple myeloma. The therapeutic potential and benefit of targeting NF-κB in cancer, and the possible complications and pitfalls of such an approach, are explored.