Rheumatology has pioneered in the study of autoantibodies by showing that they are not only involved in pathogenesis but are also highly useful as diagnostic biomarkers.The diagnostic biomarker aspect of autoimmunity has gained increasing importance in cancer and many of the insights gained in Rheumatology have contributed to understanding the significance of autoantibodies in cancer.Features of autoantibodies in rheumatic disorders: In rheumatic diseases no individual autoantibody-antigen system has sufficient combination of sensitivity and specificity to serve as a useful diagnostic biomarker.Instead, several antigen-antibody systems constructed as profiles of biomarkers are highly effective in distinguishing one disorder from another.In lupus, anti-double strand DNA and anti-Sm distinguishes it from scleroderma, where the profile is anti-DNA topoisomerase 1 and anti-centromere proteins.The autoantigensare cell components involved in universal and basic gene expression pathways, such as Sm in precursor mRNA splicing and DNA topoisomerase 1 in DNA replication and transcription [1].Features of autoantibodies in cancer: Autoantibodies in cancer target intracellular molecules referred to as TAAs (tumor-associated antigens).As in rheumatic disorders, no individual autoantibody-antigen system has sensitivity and specificity to serve as a stand-alone diagnostic marker [2].Most tumors show multiple antibody specificities and with panels of TAAanti-TAAs (analogous toprofiles) the cumulative sensitivity and specificity reaches diagnostic significance.Different tumorigenesis pathways are