It has been suggested that SHH signalling pathway promotes GBM-cell migration and invasion by increasing matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) production via the PI3K/AKT pathway [43,44] and by regulating the stem cell fraction in GBM cell lines [45]. The gene discussed is SHH; the disease is glioblastoma.