Clinical prognosis and cancer risk assessment in autoimmune diseases with anti–TIF1γ alone or concurrent with anti–Ro52 antibodies in a Taiwanese cohort

Objective: Dermatomyositis (DM), a subset of idiopathic inflammatory myopathies, affects the skin and skeletal muscles and is associated with an increased cancer risk, particularly in patients with antibodies against transcriptional intermediary factor 1γ (TIF1γ). This study aimed to evaluate the diagnostic value of anti–TIF1γ antibodies and assess their clinical significance, especially regarding cancer risk and associations with other autoimmune diseases (including overlap syndromes). Methods: In this multicenter retrospective study, we identified patients with positive anti–TIF1γ tests from Chang Gung Medical Foundation (2019–2021). Anti–TIF1γ and anti–Ro52 antibodies were detected via line blot and fluorescent enzyme immunoassay. Patients were stratified into strong-positive (++/+++) versus weak-positive (+) groups and analyzed for clinical features and cancer prevalence. Data spanned three full years and were statistically evaluated. Results: Among 84 patients with anti–TIF1γ antibody positivity, 19 (22.6%) were diagnosed with DM, including 15 patients in the strong-positive group and 4 patients in the weak-positive group, and 8 (9.5%) developed malignancy. Strong anti–TIF1γ positivity was significantly linked to dermatomyositis (46.7% vs. 7.4% in weak-positive, p < 0.05) and higher cancer incidence (20.0% vs. 3.7%, p = 0.0221). Moreover, concurrent anti–TIF1γ and anti–Ro52 seropositivity correlated with systemic lupus erythematosus (23.8% vs. 4.8%, p = 0.0211) and SLE–SjS overlap (14.3% vs. 0%, p = 0.0140). Typical skin findings included heliotrope rash, Gottron sign, and periungual telangiectasias; malignancies observed were nasopharyngeal carcinoma and lung cancer in this cohort. Conclusions: High anti-TIF1γ titers significantly increase dermatomyositis and cancer risk. Concomitant anti-Ro52 was associated with SLE and SLE–SjS overlap, emphasizing the necessity of comprehensive myositis antibody profiling for diagnosis and risk assessment.