Another important downstream target of HIC1 is SPP1, also known as Osteopontin (OPN), which is found down-regulated by our analysis as a possible effect of the loss of activity of HIC1. OPN is a multifunctional bone matrix glycoprotein [42, 43], whose production in MM cells plays a critical role in bone disease by protecting the skeleton from destruction [44]. Here, SPP1 is linked to Miyoshi myopathy.