Among the various targets of miR21 are tumor suppressors such as phosphatase and tensin homolog (PTEN), programmed cell death 4 (PDCD4), components of the p53 pathway, or transforming growth factor-β (TGF-β) signaling, resulting in increase of cell proliferation, survival and migration/invasion in tumors [54–56]. The gene discussed is PTEN; the disease is neoplasm.