Proteomics: Methodologies and applications in oncology

Few technological developments have created as much excitement and skepticism as proteomics over their potential to change clinical diagnostic and prognostic procedures. Proteomics concerns itself with the characterization and function of all cellular proteins, the ultimate determinants of cellular function. As such, it represents the end result of all mechanisms of gene regulation and thus offers tremendous potential for characterizing biology. In much the same way as what has occurred with the genome, the scientific community is coming to grips with the fact that the proteome, although enormously complex, is finite. It is conceivable that we will learn the identity of all possible proteins, including all posttranslational modifications. The rate of protein discovery continues to accelerate in large part because of improvements in mass spectrometry-based technologies coupled with improved genomic databases and bioinformatic tools. In addition, there is reason to believe that proteomics is on the verge of moving from a methodology that requires repeated proteome "discovery" to one that can more systematically profile proteomes. This review discusses current proteomic-based technologies and the efforts of scientists to move them into the clinic for use in patients treated with radiotherapy and other modalities.