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. Here, INHBA is linked to fibrodysplasia ossificans progressiva.