Combination of metformin with paclitaxel or carboplatin suppresses tumor growth and prolongs remission. A, Tumor volume (mean ± SD) in mice injected on day 0 with transformed ER-Src or MDA-MB-231 cancer cells that were untreated (NT), treated by intratumoral injections (days 10, 15, 20, 25) with 10 mg/kg paclitaxel (PTX) or treated with paclitaxel together with metformin diluted in drinking water (200 μg/ml). B, Tumor volume in mice injected with transformed ER-Src or MDA-MB-231 cancer cells that were untreated (NT), treated by intra-tumoral injections (days 10, 15, 20, 25) with 20 mg/kg carboplatin (CAR) or treated with carboplatin together with metformin diluted in drinking water (200ug/ml).