TUNEL levels elevated at surgery as compared to baseline biopsy (P<0.0001), no major difference between metformin arm and placebo arm; Ki67 labelling index and TUNEL levels at baseline & surgery in direct correlation; TUNEL levels higher with metformin than placebo in women without insulin resistance (metformin: +4%, IQR: 2–14, placebo: +2%, IQR: 0–7), while the inverse observed in those who had insulin resistance (metformin: +2%, IQR: 0–6, placebo +5%, IQR: 0–15). This evidence concerns the gene MKI67 and Insulin resistance.