IFIH1 and dermatomyositis: Interestingly, malignancy is reported to be less frequently associated with anti-MDA5 antibody-positive dermatomyositis compared to other forms of dermatomyositis.12) In a cohort study by Fiorentino et al., only 1 out of 52 patients (2%) with MDA5 antibody positivity had malignancy.2) In contrast, the incidence of malignancy associated with conventional dermatomyositis has been reported to be 20%–32% in large-scale cohort studies.13,14) Thus, although the reason remains unclear, the frequency of malignancy in anti-MDA antibody-positive dermatomyositis is considered relatively low.