ASSOCIATION STUDY BETWEEN ANTI-TIF 1γ ANTIBODY AND DEVELOPMENT OF NEOPLASIA IN THREE TERTIARY HOSPITALS.

Background: Anti-transcriptional intermediary factor 1γ (anti-TIF 1γ) antibody is robustly linked with cancer-associated dermatomyositis (DM) in adults, but its specificity varies widely between series. TIF 1γ can act either as a tumor promoter or suppressor and may behave as an autoantigen. Objectives: Investigate the association between anti-TIF 1γ antibody positivity and development of neoplasia. Methods: A retrospective chart review was conducted among patients with positive anti-TIF 1γ antibodies detected by immunoblot from March 2019 to December 2021 in three tertiary hospitals. Demographic variables, creatine kinase (CK) values, other autoantibodies, associated autoimmune diseases (AIDs) and existence or not of a cancer diagnosis were analyzed. To rule out malignancy, patients had to present a PET-CT scan without pathological findings or a chest CT scan, a gynecological study and a digestive study without alterations. A descriptive statistical analysis was performed. Results: 29 patients with anti-TIF 1γ antibodies were analyzed, 82.7% women, with a mean age of 61 years (31-96 years). The reason for requesting this antibody was: clinical features suggestive of DM in 10 patients (34.5%), muscle weakness in 9 (31%), interstitial lung disease (ILD) in 5 (17.2%), persistent CK elevation in 3 (10.3%), constitutional syndrome in 1 (3.5%) and antiphospholipid syndrome in 1 patient (3.5%). The mean time from symptoms onset to the detection of anti-TIF 1γ was 14 months (0-60 months). 10 patients (34.5%) had a diagnosis of DM; 4 patients (13.8%) systemic lupus erythematosus (SLE); one (3.5%) had a SLE/DM overlap syndrome; one patient (3.5%) subacute cutaneous lupus; one (3.5%) was diagnosed with diffuse systemic sclerosis; one patient (3.5%) limited systemic sclerosis; one patient (3.5%) antiphospholipid syndrome; one patient (3.5%) HLA-B27+ spondyloarthritis and 9 patients (31%) had no associated AIS. 5 patients (17.2%) showed ILD with different patterns: UIP (n=2), NSIP (n=2) and COP (n=1). Only 9 patients (31%) had elevated CK levels at the time of antibody determination. 10 patients (34.5%) were diagnosed with cancer: lung adenocarcinoma (n=2), small cell lung carcinoma (n=2), breast carcinoma (n=2), hepatocarcinoma (n=1), cervical cancer (n=1), ovarian carcinoma (n=1) and gallbladder adenocarcinoma (n=1). Of those, 7 patients (70%) had elevated CK levels and 6 (60%) had a diagnosis of DM. None of the patients diagnosed with cancer had ILD. In 4 patients (40%), the diagnosis of cancer was simultaneous with the diagnosis of anti-TIF 1γ antibodies; in 4 (40%), the diagnosis of the tumor preceded the finding of the antibodies; in the other 2 (20%), the finding of the antibodies preceded that of the tumor. 30-month survival after cancer diagnosis was 10%. In 17 patients (58.6%) no malignancy has been found so far in the annual cancer screening. In two patients (6.9%) no cancer screening was performed. Conclusion: In our study, 60% of patients with DM and anti-TIF 1γ presented neoplasia, a prevalence similar to that established in other series (60-80%). Furthermore, 21% of patients with antibodies and without DM were diagnosed with cancer, suggesting that anti-TIF 1γ antibodies could also be associated with neoplasia in patients without DM. Patients with ILD did not present cancer, supporting the observation of previous studies in which the presence of ILD is a marker of low risk for neoplasia in patients with DM. HyperCKemia might predict the association with neoplasia in patients with anti-TIF 1γ antibodies. REFERENCES: [1]De Vooght J, Vulsteke JB, De Haes P, Bossuyt X, Lories R, De Langhe E. Anti-TIF1-γ autoantibodies: warning lights of a tumour autoantigen. Rheumatology. 2020 Mar 1;59(3):469-477 [2]Shimizu K, Kobayashi T, Kano M, Hamaguchi Y, Takehara K, Matsushita T. Anti-transcriptional intermediary factor 1-γ antibody as a biomarker in patients with dermatomyositis. J Dermatol. 2020 Jan;47(1):64-68 [3]Masiak A, Kulczycka J, Czuszyńska Z, Zdrojewski Z. Clinical characteristics of patients with anti-TIF1-γ antibodies. Reumatologia. 2016;54(1):14-8 Disclosure of Interests: None declared Citation: , volume 81, supplement 1, year 2022, page 750Session: Scleroderma, myositis and related syndromes (POSTERS only)