P.14.5 Antibodies against TIF1-gamma in cancer associated myositis may precede cancer symptoms and persist after cancer removal

Abstract

Antibodies against TIF1-gamma have been detected in patients with cancer associated myositis (CAM) but it is not known whether the antibodies precede the diagnosis of cancer or if the antibodies persist after successful treatment of a malignancy. To analyse levels of TIF1-gamma antibodies in longitudinally collected sera taken before cancer diagnosis and after treatment of the malignancy in patients with CAM. Serum samples and clinical data were available from 54 patients with CAM. Serum levels of anti-TIF1gamma antibody were tested by ELISA using a commercially available purified recombinant protein (OriGene, Rockville, MD). Sera from 16 (29.6%) patients were positive for anti-TIF1-gamma antibodies in at least one serum sample. Of the 16 positive patients 12 had developed cancer within 3 years from myositis diagnosis, 4 after 3 years. Serum samples taken before cancer diagnosis were available from 15/54 patients and four of them were positive for anti-TIF1-gamma. One of these patients had detectable anti-TIF1gamma antibodies up to 5 years before cancer diagnosis. Of the 16 patients positive for anti-TIF1-gamma, 12 patients had died at time of our study, 7 within 1 year from cancer diagnosis. The 7 patients who died within one year had a mean antibody level of 1976 ± 304 au, the 5 patients who died after more than 1 year had a mean antibody level of 1036 ± 555 au ( p = 0.003). Four patients were still alive at time of the investigation, between 2–13 years after cancer treatment. They were all in remission from cancer disease. Two patients became negative for anti-TIF1-gamma antibodies, these two patients were among the patients in remission at follow up. Anti-TIF1-gamma antibodies can be detected before cancer diagnosis and may thus become a helpful marker to alert for cancer in patients with myositis. The levels of anti-TIF1-gamma antibodies seem to be a prognostic marker for survival in CAM.