IGF1R and carcinoma: These findings suggest that some of the hyperplastic or angiogenic islets develop highly invasive carcinomas (variable sizes) without progressing through a noninvasive IT stage (>1 mm in diameter), a phenotype first observed in bitransgenic mice that express both SV40 T antigen and a receptor tyrosine kinase, the insulin-like growth factor (IGF) 1 receptor (IGF1R), in the pancreatic islets [23].