Brain tumours are the sixth most common cancer in adults, accounting for 2% of all tumours, and the most common form of solid cancer in children. They are a significant cause of neurological morbidity and mortality in both age groups and there is an urgent requirement for the development of effective new treatments, which will only be achieved through better understanding of their biology. In our research programme, we are defining the genetic aetiology of brain tumours arising in both paediatric and adult populations. Our combined approach of genomic and expression analysis is providing a unique insight into the genetic mechanisms of tumour development and clinical behaviour (including tumour recurrence, malignant progression, response to therapy and length of survival), enabling us to identify novel prognostic markers and therapeutic targets.