Tumour necrosis factor-alpha (TNF-alpha) is an important inflammatory factor that acts as a master switch in establishing an intricate link between inflammation and cancer. A wide variety of evidence has pointed to a critical role of TNF-alpha in tumour proliferation, migration, invasion and angiogenesis. The function of TNF-alpha as a key regulator of the tumour microenvironment is well recognised. We will emphasise the contribution of TNF-alpha and the nuclear factor-kappaB pathway on tumour cell invasion and metastasis. Understanding the mechanisms underlying inflammation-mediated metastasis will reveal new therapeutic targets for cancer prevention and treatment.