The insulin-like growth factor 1 receptor (IGF-1R) is an important signaling 
molecule in cancer cells and plays an essential role in the establishment and 
maintenance of the transformed phenotype. Inhibition of IGF-1R signaling thus 
appears to be a promising strategy to interfere with the growth and survival of 
cancer cells. Different classes of molecules, e.g., antisense RNA, monoclonal 
antibodies and dominant negative IGF-1R gene variants, have been employed 
towards this aim. These agents have been able to reverse the transformed 
phenotype in several rodent and human cancer cell lines. The application of 
peptide aptamers specifically binding to the IGF-1R represents a novel approach 
to target IGF-1R signaling. The integration of peptide aptamers into targeted 
protein degradation vehicles and their transduction into cells allows the 
temporary elimination of the receptor protein. This review summarizes recently 
published data about inhibition of IGF-1R signaling and provides a perspective 
on upcoming possibilities.