ANO1 and intrahepatic cholangiocarcinoma: Particularly, ANO1 is a strong candidate as a pacemaker channel because of the expression of ANO1, failing of slow waves in ANO1 knockout mouse, blocking of slow waves by Ca2+‐activated Cl− channel blockers in intact mouse and human intestine and single‐channel recording of Ca2+‐activated Cl− channels in ICC.14, 15