LEP and hepatocellular carcinoma: Adiponectin attenuates leptin-induced signal transducer and activator of transcription 3 (STAT3) and protein kinase B (Akt) activation by upregulating suppressor of cytokine signaling 3 (SOCS3), a physiological negative regulator of leptin signal transduction, thus inhibiting leptin-induced hepatoma cell proliferation (38).