Reactive Nitrogen Posttranslational Modifications of Proteins in Carcinogenesis 127

Molecular and epidemiological evidence has established important roles for reactive oxygen/reactive nitrogen species (ROS/RNS) in tumor cells, supporting stromal cells and infiltrating leukocytes in tumor initiation and progression. RNS-dependent posttranslational protein modifications (tyrosine nitration and S-nitrosylation) are well-accepted markers of the tissue inflammation, but also modulate the functions of proteins critical in carcinogenesis and tumor growth.