PIR and hyperplasia: The pIGF1R/pIR pathway is of particular interest in relation to endometrial cancer development, and at least one previous study reported upregulation of pIGF1R/pIR in complex atypical endometrial hyperplasia, a putative precursor lesion for endometrial cancer, as well as in grade 1 endometrial cancers as compared with normal endometrium [32].