Insulin and insulin-like growth factor-I (IGF-I) receptor overexpression in breast cancers leads to insulin/IGF-I hybrid receptor overexpression: evidence for a second mechanism of IGF-I signaling. - Pandini,G.; Vigneri,R.; Costantino,A.; Frasca,F.; Ippolito,A.; Fujita-Yamaguchi,Y.; Siddle,K.; Goldfine,I.D.; Belfiore,A. (Clin Cancer Res, 1999)