Selected inflammatory conditions increase the risk of cancer. An inflammatory component is present also in the micro-environment of tumours epidemiologically unrelated to inflammation. An intrinsic (driven by genetic events that cause neoplasia) and an extrinsic (driven by inflammatory conditions which predispose to cancer) pathway link inflammation and cancer. Smouldering inflammation in the tumour microenvironment contributes to proliferation and survival of malignant cells, angiogenesis, metastasis, subversion of adaptive immunity, response to hormones, and chemotherapeutic agents. Emerging evidence also suggests that cancer-related inflammation promotes genetic instability. Thus, cancer-related inflammation represents a target for innovative diagnostic and therapeutic strategies.