Development of solid tumours depends on new vessel formation by angiogenesis. Angiogenic endothelial cells (ECs) express different genes compared with quiescent ECs. Evidence suggests that non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin protect against bowel cancer. Multiple mechanisms may be responsible, but aspirin may target angiogenic tumour ECs. The aims of this project were firstly, to monitor NSAID effects on angiogenesis, and determine if this was by cyclooxygenase inhibition, and secondly to investigate novel genes expression in tumour ECs to identify targets for anti-angiogenic cancer therapy.