MiR-21-5p has been reported to be one of the most abundant in exosomes derived from GH-secreting pituitary adenoma and downregulated the Programmed cell death 4/Activator protein 1 (PDCD4/AP-1) pathway by targeting PDCD4 and SMAD Family Member 7 (Smad7) (67) with subsequent distant effects that have been shown in vitro, specifically osteoblast proliferation, differentiation and mineralization (67). Here, SMAD7 is linked to pituitary gland adenoma.