Anti-Ro52 antibody (Ab) reactivity is highly prevalent in autoimmune rheumatic diseases (ARDs), mainly Sjögren's syndrome (SjS) and systemic lupus erythematosus (SLE), but also in other inflammatory disorders. Thorough assessment of the prevalence, clinical significance and epitope specificity of Ro52-autoAbs in cancerous diseases is still lacking.
Anti-Ro52 Ab reactivity was tested in a large cohort of 490 patients with various malignant diseases. Ro52-autoAb epitope mapping by an in house line immunoassay was carried out using 5 recombinant Ro52 polypeptides spanning Ro52.
Anti-Ro52 abs were significantly more prevalent in patients with ovarian cancer (30%) compared to patients with 6 other malignant diseases (median 8.1%, range 5.9-15.8%). The presence of anti-Ro52 abs in patients with ovarian cancer was strongly associated with better overall survival. Ro52 epitope mapping of patients with ovarian cancer was dissimilar to that of SLE and SjS ARDs, less frequently recognizing Ro52-1 and Ro52-4 fragments compared to patients with SLE and SjS.
We demonstrate for first time an unexpectedly high frequency of anti-Ro52 abs in patients with ovarian cancer, their presence indicating better overall survival. Their distinguishing epitope profile may suggest a non-SLE or SjS-related stimulus for autoAb production.