Objective: Anti‐p155 autoantibody, which was recently described in adult patients with dermatomyositis (DM), seems to be associated with cancer in this population. We performed a systematic review and meta‐analysis to ascertain the accuracy of anti‐p155 testing for the diagnosis of cancer‐associated myositis.Methods: We searched relevant databases, with no restrictions on study design or language, for original studies that included adult patients with probable/definite DM or amyopathic DM who were evaluated for neoplasm and anti‐p155 status. Pooled sensitivity and specificity were calculated using a bivariate model. We computed the diagnostic odds ratio (OR), likelihood ratios (LRs) for positive and negative test results, positive and negative predictive values, and the summary receiver operating characteristic (SROC) curve. Statistical heterogeneity between studies was assessed using the I² statistic, and 95% confidence intervals (95% CIs) were computed for the parameters studied.Results: Six studies including a total of 312 adult patients with DM were selected. The pooled sensitivity of anti‐p155 for diagnosing cancer‐associated DM was 78% (95% CI 45–94%), and specificity was 89% (95% CI 82–93%). The diagnostic OR was 27.26 (95% CI 6.59–112.82), and LRs for positive and negative test results were 6.79 (95% CI 4.11–11.23) and 0.25 (95% CI 0.08–0.76), respectively. Heterogeneity was substantial except with regard to the LR for a positive test result. The area under the SROC curve was 0.91 (95% CI 0.88–0.93). Taking the pooled prevalence of 17% as pretest probability, anti‐p155 had a positive predictive value of 58% and a negative predictive value of 95%.Conclusion: Our findings indicate that anti‐p155 autoantibody determination is useful for diagnosing cancer‐associated myositis and guiding disease management.

Currently available data support the idea that inflammatory myopathies, particularly dermatomyositis, are paraneoplastic diseases. Cancer screening is usually recommended in patients with these conditions, but there is no consensus regarding how and how often screening should be performed. This review will address recent advances in our understanding of the relationship between cancer and myositis and describe new data regarding the best approach for cancer screening in myositis patients. A newly described autoantibody to a 155-kDa nuclear protein, identified as transcription intermediary factor 1-gamma (TIF1-γ), has proven useful for cancer screening in patients with dermatomyositis. Occult tumor detection by PET/computed tomography (PET/CT) seems to be a good alternative to broad conventional screening. A combination of both methods, detection of autoantibodies against p155 and PET/CT study, may be the best approach to ascertain the presence of occult malignancy in patients with dermatomyositis. Advances in immunology and imaging techniques are increasing the accuracy of occult malignant cancer detection in dermatomyositis patients. Nevertheless, the diagnosis of cancer in this population remains elusive in some cases. Further investigation is needed to improve our knowledge of the link between myositis and cancer.

A new autoantibody against a 155-kDa protein has been described in patients with myositis. We conducted a study to determine the occurrence and types of cancer occurring in a cohort of patients with polymyositis (PM) or dermatomyositis (DM) and analyzed the value of this autoantibody as a serologic marker of cancer-associated myositis (CAM). Serum samples from all patients were examined by protein immunoprecipitation assays with HeLa cells to determine the presence of a 155-kDa protein band. HLA-DRB1 and DQA1 typing was performed by polymerase chain reaction-reverse sequence specific oligonucleotide. Statistical analyses were carried out with the Mann Whitney U and Fisher exact tests. Associations were determined using odds ratios (ORs) with 95% confidence intervals (CI). Eighty-five patients with myositis (20 PM and 65 DM) were included. CAM was detected in 16 patients (19%), 14 with DM. The shawl sign rash was significantly more frequent in patients with CAM than in those without (p < 0.01). Adenocarcinoma was the most frequent type of cancer (87.5%). Anti-p155 autoantibody was found in 1 of the 20 (5%) patients with PM and in 15 of the 65 (23%) patients with DM. A relationship between anti-p155 and CAM was found in DM patients (OR, 23; 95% CI, 5.23-101.2). The HLA-DQA1*0102 allele was not found in any of the anti-p155-positive patients. The prevalence of CAM in our cohort was 19%. Autoantibody against p155 was highly related to CAM and could be a reliable marker of cancer in patients with DM. Abbreviations CAM = cancer-associated myositis, CI = confidence interval, DM = dermatomyositis, OR = odds ratio, PM = polymyositis.