TGFB1 and cervical carcinoma: To explore the potential effect of metformin for antagonzing the anti-apoptosis effect of TGF-β1 on cervical carcinoma cells by Annexin V-FITC and propidium iodide (PI) staining, we detected the effect of metformin with and without TGF-β1 on the apoptosis of HeLa (Figure 2C) and SiHa (Figure 3C) cells.