CBX1 and intrahepatic cholangiocarcinoma: Taking advantage of the yet unprecedented possibility to selectively stimulate SMC using optogenetics, we were able to reveal differences between ICC-SMC heterocellular and SMC-SMC homocellular coupling: The same concentration of CBX which completely abolished spontaneous activity deriving from ICC had still significant, but less pronounced effects on light-induced force generation and Ca2+ transients.