Identification of Phosphoproteins and their Impact as Biomarkers in Cancer Therapeutics

Many cellular processes are regulated by the reversible reaction of protein phosphorylation on serine, threonine and tyrosine residues. Deregulation of the signal transduction cascade upsets this well-balanced system and has been implicated in many diseases, including cancer. Identification of the proteins and post-translational modifications (PTMs) involved in the breakdown of certain cell signaling pathways provide unique insight into the disease's pathology. The importance of phosphorylation on a molecular level has been implicated specifically within signaling pathways involved in the pathogenesis of cancer. Emerging phosphoproteomic technologies have proven to be valuable tools in identifying new biomarkers, which presents an opportunity to probe phosphoproteins in specific cancer related pathways for both diagnosis and therapeutic exploitation. This review will discuss the development and impact of current phosphoproteomic identification and quantification methodologies and the utility of these technologies to assist in the determination of phosphoproteins as potential biomarkers and/or drug targets in cancer.