Karolinska Institutet, Solna, Karolinska University Hospital, Center for Molecular Medicine, and Region Västmanland, Reumatologkliniken, Västmanlands sjukhus Västerås, Stockholm, Sweden.
Vilnius University and State Research Institute for Innovative Medicine, Vilnius, Lithuania.
Arthritis Care Res (Hoboken). 2018 Apr;70(4):648-651. doi: 10.1002/acr.23325.
An association between cancer and dermatomyositis (DM) is well recognized. The high frequency of malignancies detected close to DM diagnosis suggest that DM can be a paraneoplastic syndrome. Recently, anti-transcription intermediary factor 1γ (anti-TIF1γ) has been discovered to be associated with cancer and with DM. A meta-analysis reported the pooled sensitivity of anti-p155 for diagnosing cancer-associated DM to be 78% and the specificity to be 89%. Thus, anti-TIF1γ has shown promising results as a marker for cancer-associated DM. However, none of the studies evaluated the association of anti-TIF1γ with cancer with or without rheumatic diseases other than DM. To clarify the specificity of anti-TIF1γ antibodies as a biomarker for cancer-associated DM, we analyzed the frequency of anti-TIF1γ antibodies in other cancer-associated rheumatic syndromes, as well as in cancer patients and healthy controls.
Sera from patients with paraneoplastic rheumatic syndrome (n = 91), patients with solid cancer (n = 95), and healthy controls (n = 80) were analyzed for the frequency of anti-TIF1γ IgG by enzyme-linked immunosorbent assay using a commercially available recombinant TIF1γ protein as coating antigen. The cutoff value was calculated by adding 2 SD to the mean optical density value of 80 healthy controls.
The rate of anti-TIF1γ IgG positivity was 3.3% (n = 3) in patients with paraneoplastic rheumatic syndrome, 3.1% (n = 3) in cancer patients, and 1.3% (n = 1) in healthy controls. There were no significant differences in positivity between the groups (P < 0.05).
Anti-TIF1γ antibodies are rarely present in patients with solid cancers or paraneoplastic rheumatic syndromes. This finding strengthens the approach to using anti-TIF1γ IgG as a marker for cancer-associated DM.
癌症与皮肌炎（DM）之间的关联已得到充分认识。在 DM 诊断附近检测到的恶性肿瘤的高频率表明 DM 可能是一种副肿瘤综合征。最近，发现抗转录中介因子 1γ（抗-TIF1γ）与癌症和 DM 相关。一项荟萃分析报告称，抗-p155 诊断癌症相关 DM 的汇总敏感性为 78%，特异性为 89%。因此，抗-TIF1γ 已显示出作为癌症相关 DM 标志物的有前途的结果。然而，尚无研究评估抗-TIF1γ与癌症的关联，也未评估除 DM 以外的其他风湿性疾病与癌症的关联。为了阐明抗-TIF1γ 抗体作为癌症相关 DM 的生物标志物的特异性，我们分析了其他癌症相关风湿综合征以及癌症患者和健康对照者中抗-TIF1γ 抗体的频率。
使用商业上可获得的重组 TIF1γ 蛋白作为包被抗原，通过酶联免疫吸附试验分析了副肿瘤性风湿综合征患者（n=91）、实体癌患者（n=95）和健康对照者（n=80）血清中抗-TIF1γ IgG 的频率。通过将 80 名健康对照者的平均光密度值加 2 个标准差来计算截止值。
副肿瘤性风湿综合征患者中抗-TIF1γ IgG 阳性率为 3.3%（n=3），癌症患者为 3.1%（n=3），健康对照者为 1.3%（n=1）。各组之间的阳性率无显著差异（P<0.05）。
抗-TIF1γ 抗体在实体癌或副肿瘤性风湿综合征患者中很少出现。这一发现加强了使用抗-TIF1γ IgG 作为癌症相关 DM 标志物的方法。
