The up-regulation of IL1B, IL6 and CCL7 genes by Activin-A in FOP-ML was inhibited by dexamethasone (Figs. 5A–C), but the expression of INHBA was negligibly affected (Fig. 5D), suggesting the limited therapeutic effects of corticosteroids for FOP. The gene discussed is IL1B; the disease is fibrodysplasia ossificans progressiva.