MMP2 and glioblastoma: Demuth et al. (2007) have identified the MKK3 as a key activator of GBM invasiveness through p38 activation, both in vitro and in vivo. Irradiation is often part of the GBM treatment scheme, although, in cells that present mutant PTEN it was described that irradiation can activate p38/Akt and PI3K/Akt signaling pathways, increasing MMP-2 expression and intensifying invasiveness (Park et al., 2006).