Emerging role of nitric oxide in cancer.

The small molecule nitric oxide has generated an exponential amount of research since its identification as a biological messenger in 1987. It is a free radical, the actions of which are diverse, and many are still poorly understood. An area of great interest is the role of nitric oxide in the growth and metastasis of solid tumours, where it seems to have a complex action including both inhibitory and tumour-promoting activity. Over 28,000 research papers have been written on nitric oxide, with only a minority concentrating on the head and neck. In this review, we give a brief history of this fascinating molecule, concentrating on its possible interest to oral and maxillofacial surgeons.