Proteomics: a long and winding road to medical diagnostics

The addition of protein biomarker panels to the cancer diagnostic armamentarium is an area of considerable interest in medicine. The discovery that proteins and peptides are 'leaked' by tumors into clinically accessible bodily fluids such as blood and urine has led to the possibility of diagnosing cancer at an early stage or monitoring response to treatment simply by collecting these fluids and testing for the presence of cancer-related biomarkers. Prostate-specific antigen and cancer antigen-125 are examples of blood-borne cancer protein biomarkers that are now being used in the clinic. However, the measurement of individual biomarkers has clinical limitations with respect to both sensitivity and specificity. For this reason, combinations of protein/peptide analytes are under intense investigation, as biomarker panels can potentially bring greater sensitivity and specificity to cancer screening than any one analyte alone.

This perspective article highlights some of the challenges that hinder the translation of proteomics to clinical diagnostics.

Tremendous advances have been made in genomics over the past decade, and this field holds great promise for understanding, treating and even preventing many forms of cancer; although genes are the 'recipes' of the cell, proteins are the critical molecular players that drive both normal and disease physiology. If the potential of personalized medicine is to be realized, it needs to include this next generation of molecular diagnostics.