IGF1R and cancer: We summarized the theoretical basis that support our hypothesis as following: (1) the caloric restriction effect and other anti-neoplastic mechanisms make metformin good choice in cancer therapy (2) anti-IGF-1R mAbs targeting therapy is promising approach against cancer, including NSCLC (3) inhibition effects on IGF-1R signaling system highlighting metformin as a candidate as an adjuvant in anti-IGF-1R system therapy (4) anti-IGF-1R mAb targeting therapy may benefit from metformin for its hypoglycemic property by reducing side effects.