Because early paediatric clinical trials of new PI3K or PI3K/mTOR inhibitors, as single agents and in combination with other cancer treatments, are planned in glioblastoma, we have focussed on this tumour type in our current work and we are building on this by investigating inhibition in vivo in orthotopic models of paediatric glioblastoma established in our Unit. The gene discussed is PIK3CA; the disease is cancer.