HRH3 and hepatocellular carcinoma: For example, activation of H3R by agonists induced the proliferation of pancreatic carcinoma PANC-1 cells and breast carcinoma MDA-MB-231 cells [9, 11], while activation of H3R by an agonist suppressed the proliferation of hepatoma McA-RH7777 cells and cholangiocarcinoma Mz-ChA-1 cells [31, 32].