CDK4 and nasopharyngeal carcinoma: The Na+-K+-2Cl− co-transporter 1 (NKCC1) is an important cell volume regulator that participates in cell migration [31]; ClC-3 chloride channel proteins regulate the cell cycle by up-regulating cyclin D1-CDK4/6 through suppressing p21/p27 expression in nasopharyngeal carcinoma cells [32]; ANO1 is a calcium-activated chloride channel that is up-regulated in various cancers, including gastrointestinal stromal tumor, squamous cell carcinoma of the upper aerodigestive tract and the esophagus (ESCC), and pancreatic cancer [33, 34].