In MCF-7 and SK-BR-3 breast cancer cells, Wei et al. found that leptin, through a mechanism dependent on the activation of the canonical PI3K/Akt pathway and the overexpression and activation of pyruvate kinase M2 (PKM2), promotes the expression of vimentin, fibronectin, and Twist and the downregulation of E-cadherin [111]. Here, FN1 is linked to breast cancer.