Cancer Stem Cells: Proteomic Approaches for New Potential Diagnostic and Prognostic Biomarkers

The recent identification of cells with stem cell-like behaviour in several types of human cancers has opened new avenues for a better understanding of molecular mechanisms and intracellular signalling events that drive a complex degenerative process such as carcinogenesis. The investigation of the pathophysiology of CSC represents an interesting subject for proteomic analysis that in last decade has exploded with thousand of experimental and clinical studies examining various aspects of oncology. Proteomic approaches have produced a wealth of data identifying proteins that regulate self-renewal, pluripotency and differentiation of stem cells, even though with all the limits related to protocol variability that renders rather difficult to create a definitive proteome profile. More recently, several studies directly examining CSCs proteome or showing in cancer cell proteome altered expression levels of proteins that are actually considered characteristic of stemness have been published. The possibility of applying proteomic strategies to the study of CSCs and of the complex series of molecular interactions and phosphorylations events that occur at level of protein components of the signalling pathways involved in self-renewal and carcinogenesis could shed new light on the molecular mechanisms that form the basis of this process, with all potential clinical applications related to the physiopathology of CSCs.