Estrogens could be able to modulate the activity of several enzymes involved in HCC appearance: signal transducer and activator of transcription (STAT) protein family, suppressors of cytokine signaling (SOCS) proteins, ERK, and G protein-coupled estrogen receptor 1 (GPER) proteins [38,39]. The gene discussed is GPER1; the disease is hepatocellular carcinoma.