Genomics, proteomics and metabolomics: their emerging roles in the discovery and validation of rheumatoid arthritis biomarkers.

Rheumatoid arthritis (RA) is an autoimmune inflammatory rheumatic disease which affects several organs and tissues, predominantly the synovial joints. Despite major advances, the aetiology of this disease is not completely understood. Although several biomarkers are routinely used in RA management and some of them can be detected even prior to the onset of the clinical disease, there is a high demand for novel biomarkers to further improve the early diagnosis of RA. The '-omics' techniques that have emerged and have been developed in recent years have allowed researchers to improve their knowledge of the aetiopathology of RA. At the same time, advances in screening technologies offer an excellent opportunity to find new biomarkers potentially useful for early diagnosis, stratification of patients, and even prediction of a better response to a specific therapy. This review describes what is known about the methodologies used in the discovery of novel biomarkers in RA, along with the findings of these methodologies, with specific attention to recent advances in the fields of genomics, proteomics and metabolomics.