Chloride intracellular channel protein 1 is a protein that in humans is encoded by the CLIC1 gene. Chloride channels are a diverse group of proteins that regulate fundamental cellular processes including stabilization of cell membrane potential, transepithelial transport, maintenance of intracellular pH, and regulation of cell volume. Chloride intracellular channel 1 is a member of the p64 family; the protein localizes principally to the cell nucleus and exhibits both nuclear and plasma membrane chloride ion channel activity. Membrane insertion seems to be redox-regulated and may occur only under oxydizing conditions. Involved in regulation of the cell cycle. Mainly cytoplasmic expression in most glandular epithelial cells, also membranous expression in renal tubules. CLIC1 is frequently upregulated in multiple human malignancies and has been demonstrated to play a critical role in cell proliferation, apoptosis, and invasion. However, limited is known about its expression, biological functions, and action mechanism in oral malignancies.