STAT3 and breast cancer: LEPR, STAT3, JUN (c-Jun), FOS (c-Fos) were expressed in both MCF7 and MCF10AT1 breast cancer cell lines (Fig 5A) indicating the presence of LEPR signalling components in these cells, while western blotting after chronic leptin treatment indicated increased STAT-3 phosphorylation, demonstrating active leptin signalling (Fig 5B), consistent with the observed proliferation effect (Fig 1).