Loss of PTEN and activation of AKT were suggested to be associated with increased tumour cell sensitivity to the mTOR inhibitors (Kurmasheva, Huang & Houghton, 2006), although only the loss of PTEN expression was used, in clinical trials, as a marker to evaluate glioblastoma sensitivity to rapamycin treatment (Cloughesy et al., 2008). The gene discussed is PTEN; the disease is glioblastoma.