Strong correlation between cancer progression and anti-transcription intermediary factor 1γ antibodies in dermatomyositis patients.

OBJECTIVES: Transcription intermediary factor 1γ (ΤΙF1γ) protein is known as a tumour suppressor that promotes cellular differentiation. Autoantibodies to ΤΙF1γ have a strong clinical association with cancers associated with dermatomyositis (DM). This study aims to identify the clinical characteristics of cancers in anti-ΤΙF1γ antibody-positive adult patients with DM.

METHODS: This retrospective analysis covered 160 adult DM patients who visited Nagoya University Hospital or collaborating medical centres between 2003 and 2016. Anti-TIF1γ antibody and other myositis-specific autoantibodies were detected by ELISA. Based on a review of medical charts, the cancers were staged according to the TNM Classification of Malignant Tumours of the Union for International Cancer Control and were divided into the two groups of "advanced" or "non-advanced" according to the stage classification.

RESULTS: Forty-one of the 160 (26%) patients had cancer. The incidence was significantly higher in the anti-TIF1γ-positive patients than in the anti-TIF1γ-negative patients (23/34=68% vs. 18/126=14%, p<1x10-6). Anti-TIF1γ-positive patients with cancer were found more frequently in the "advanced" group than in the "non-advanced" group (21/23=91% vs. 9/18=50%, p<0.0046). The intervals between DM diagnosis and cancer diagnosis were significantly shorter in the anti-TIF1γ-positive patients than in the anti-TIF1γ-negative patients (p=0.047).

CONCLUSIONS: Not only did anti-TIF1γ antibodies correlate strongly with malignancy in DM patients, but cancers were also significantly more advanced in anti-TIF1γ-positive DM patients than in anti-TIF1γ-negative patients. Cancers in such cases were very frequently found close to the time of the DM diagnosis.