IGF1R and prostate neoplasm: Moreover, over-expression of human IGF-I in prostate epithelial cells in a transgenic mouse model led to activation of the IGF-IR and spontaneous tumorigenesis in prostate epithelium (DiGiovanni et al., 2000), while suppression of IGF-IR inhibited prostate tumor cell growth and invasion in rats (Burfeind et al., 1996).