When ectopically induced, miR-503 triggers apoptosis and leads to G0/G1 cell cycle arrest, by negatively regulating insulin-like growth factor-1 receptor (IGF-1R) and consequently weakening the functionality of the IGF-1R/PI3K/AKT signaling pathway, a core pathway in GBM oncogenesis [155]. The gene discussed is IGF1R; the disease is glioblastoma.