New Assay Detects Dermatomyositis Patients At Risk of Malignancy

Fiorentino DF, Chung LS, Chrisophter-Stine L et al. Most patients with cancer-associted dermatomyositis have antibodies to nuclear matrix protein NXP-2 or transcription intermediary factor 1-gamma. Arthritis & Rheumatism (2013) Published online Sept. 3

A multicenter team has determined that more than many dermatomyositis patients carry either one or the other of two antibodies previously associated with malignant cells from patients with this condition. The team hopes the finding will evolve into a test that allows rheumatologists to identify dermatomyositis patients in greatest need of vigilance for malignancy, which is associated with the condition..

In vitro tests have determined that antibodies against anti-transcriptional intermediary factor-1 (TIF-1) and nuclear matrix protein NXP-2 are associated with malignancy in dermatitis. Having created an immunoassay for the two antibodies, the team analyzed sera from 213 dermatomyositis patients seen in clinics at Stanford and Johns Hopkins university medical centers. Antibodies against TIF-1 turned up in 38% of patients and 17% tested positive for NXP-2. Reactivity against either antibody correctly identified 83% of patients with comorbid cancer and dermatomyositis.

In order to be applied in rheumatology practice, these results would need to be validated in additional cohorts of patients, and the test would have to be developed as a clinical assay, which would again need to be validated in numerous cohorts. The authors say they are not aware of any commercial development but hope that interest will evolve in developing a commercially available test.