Studies have been performed showing the cancer-preventive effects of metformin in tumor-bearing rodents with obese or diabetic backgrounds involving targeting insulin, AMPK, fat metabolism, antiapoptotic molecules, Signal Transducer and Activator of Transcription 3 (Stat3) and Extracellular Signal-Regulated Kinase (ERK) [27,28,29,30,31]. Here, INS is linked to cancer.