We treated two high-GPER-expressing HCC cell lines (i.e., HCCLM3 and SMMC-7721) and a low-GPER-expressing HepG2 cell line with the GPER-specific agonist G1, and measured GPER/EGFR signals and their downstream pathways. The gene discussed is GPER1; the disease is hepatocellular carcinoma.