miR-17~106 family is firstly identified as oncogenic factors in a variety of tumor types by suppressing the expression of anti-tumor genes, such as Cdkn1a (p21), Pten, Timp2, Smad7, and Bim [10–13]. During the CNS development, the functional analyses of miR-17~106 family in the regulation of NPCs majorly focus on the miR-17~92 cluster which plays an important role in maintaining self-renewal and regulating neurogliogenic decision of NPCs [14–17]. The gene discussed is SMAD7; the disease is neoplasm.