LEP and ovarian carcinoma: Besides, inhibition of established tumorigenic effects of leptin via direct inhibition of the PI3K pathway (Choi et al., 2011; Uddin et al., 2009; Hoffmann et al., 2016), which is activated in ovarian cancer cells, has also been demonstrated by numerous studies (Keum et al., 2015; Chen et al., 2013; Hoffmann et al., 2016).