Nitric oxide synthases, cyclooxygenase-2, nitrotyrosine, and angiogenesis in chondrosarcoma and their relation to prognosis.

Background: The localization in tumor tissue of various markers by immunohistochemistry can help to establish a diagnosis or predict prognosis. Nitric oxide is associated with tumors and has been studied indirectly by nitrotyrosine analysis and with use of the enzymes nitric oxide synthase (NOS)1, NOS2, and NOS3. Nitric oxide reacts with superoxide anions to yield peroxynitrite, which has toxic effects on genes.