Investigation of Myositis and Scleroderma specific autoantibodies in patients with lung cancer

Background: The close temporal association between onset of some connective tissue diseases and cancer suggests a paraneoplastic association. Adult scleroderma patients with anti-RNA polymerase III autoantibodies and adult dermatomyositis patients with anti-TIF1 or anti-NXP2 autoantibodies have a significantly increased risk of developing cancer. Autoantibodies may serve as biomarkers for early detection of cancer and also could be relevant for prediction of responses to immune therapies. We aimed to test whether myositis and scleroderma specific or associated autoantibodies are detectable in individuals with lung cancer.

Methods: Serum from 60 Caucasian lung cancer patients (30 with small cell lung
cancer, 30 with non-small cell lung cancer) was screened for myositis and scleroderma specific and associated autoantibodies by radiolabelled immunoprecipitation.

Results: Anti-TIF1, anti-NXP2 or anti-RNA polymerase III autoantibodies were not detected in any of the 60 lung cancer patients. Anti-glycyl-tRNA synthetase (anti-EJ) autoantibodies were detected in one patient with non-small cell lung cancer. No other known myositis or scleroderma autoantibodies were identified.

Conclusions: Myositis and scleroderma specific autoantibodies, including anti-TIF1, anti-NXP2 and anti-RNA polymerase III, are rare in lung cancer patients without an autoimmune disease. We report here the first case of anti-EJ autoantibodies being detected in a lung cancer patient without clinical or radiographic evidence for the antisynthetase syndrome.