4. Personalized medicine

4.1 Biomarkers: definition and issues

A biomarker is a piece of biological data – it may be a genetic mutation, a protein, a metabolite, etc. – that can be correlated in a statistically significant way with a biological process (the onset of a pathology, the development of this pathology, recurrence, good or bad metabolization of a drug, in particular), and can be used as an aid to diagnosis, prognosis and/or therapeutic decision-making. The identification, characterization and validation of biomarkers already appear to be strategic for healthcare systems in developed countries. Today, these systems face considerable challenges:

• ageing populations and the fact that many of the diseases that pose thorny public health problems are now chronic diseases,...