In the cell line HCC 1937 (Fig. 3, sub-figure c) an increase in cell proliferation was observed when stimulated with leptin, reaching a maximum effect at 24 hours of stimulation with an increase of 71.74% for 10 ng/mL, 57.3% for 100 ng/mL and 70.3% for 200 ng/mL compared to the control, subsequently a decrease in proliferation is observed. This evidence concerns the gene LEP and hepatocellular carcinoma.