LEP and prostate cancer: Effects of long-term, even mild, overweight on prostate cancer risk could be mediated by several biological mechanisms, implicating sex hormones (androgens and oestrogen) (Nomura, 2001), leptin, and insulin-like growth factor (IGF)-I (Chan et al, 1998; Calle, 2000; Hsing and Devesa, 2001; Pollak, 2001).