We have previously determined the insulin-like growth factor 1 receptor (IGF1R) to be amplified and overexpressed in Wilms tumour. In order to probe the efficacy and mechanisms of action of various inhibitors of the receptor, we have carried out expression profiling of Wilms tumour cells treated with 5x IC50 of the compounds PPP and NVP-AEW541 over a 24 hour time-course.