Lipid accumulation has been described as a consequence of reduced FAO inhibition.11 Using gas chromatography, the effect of metformin treatment on cellular triglyceride fatty acid (TGFA) content was assessed in three oestrogen/progesterone receptor (ER/PR) positive human breast cancer cell lines (MCF7 and T47D, BT474) and three ER/PR negative cell lines (MDA-MB-231, MDA-MB-468 and MDA-MB-157). The gene discussed is PGR; the disease is breast carcinoma.