In a study using spontaneously obese rats with impaired glucose tolerance (WNIN/GR-Ob rats) to explore related molecular mechanisms, elevated expression of signaling molecules including IGF-1, IGF-1R, PI3 kinase, pAkt, and ER was observed in mammary tumor tissues of obese rats compared to lean rats, promoting mammary cell proliferation and dissemination [43]. The gene discussed is IGF1; the disease is breast cancer.