IGF1 and cancer: To examine the potential regulation of the expression and activation of IGF-IR and downstream signaling mediators by metformin in different types of endometrial carcinoma, Type I (Ishikawa, ECC-1) and Type II (USPC-2, USPC-1) cancer cells were treated with metformin for 24 h, in the presence or absence of IGF-I during the last 10 min (Figure 1A).