Using a transgenic mouse model ofadenocarcinoma of the prostate (TRAMP), investigators found high levels of IGF-1 inbasal epithelial cells of the prostate that could activate the IGF-1R and result inspontaneous tumorigenesis in prostate epitheliums Other transgenic models thatexpress the IGF-1R constitutively showed aberrant development of the mammary glandsand rapid development of salivary and mammary adenocarcinomas.45 Expression of an IGF-1R dominant negativemutant in Ewing’s sarcoma cells markedly decreased proliferation and inducedapoptosis. Here, IGF1R is linked to Ewing sarcoma.