Cancers are characterized by uncontrolled cell growth, increased cell survival, remodeling of tumor microenvironment, neovascularization, invasion and metastasis. Each of these processes involves perturbation of key regulatory pathways. Disruption of these pathways is often caused by mutations and modifications in proteins that occupy hub positions, resulting in either disruption of their function or aberrant activation. Protein kinases are an excellent example of a class of enzymes whose activity if often found to be deregulated in diseases including cancers [1,2]. Protein kinases mediate the covalent addition of phosphate group to amino acid side chains in proteins thereby modifying them post-translationally. The hydroxyl groups of serine, threonine, tyrosine or histidine amino acid side chains are the most common phosphoacceptor sites on proteins. Reversible protein phosphorylation plays an important role in essentially every aspect of life including cellular processes that mediate metabolism, cell cycle progression, proliferation, apoptosis, differentiation, cytoskeletal dynamics, cell migration, immune response, and intracellular transport.