Mps1 (Monopolar Spindle 1 protein kinase) is a crucial cell cycle regulatory kinase primarily involved in the spindle assembly checkpoint during mitosis. This kinase is localized in the cell nucleus and the spindle assembly checkpoint complex, monitoring the correct attachment of chromosomes to the spindle. The activity and expression of Mps1 are tightly regulated throughout the cell cycle to ensure the proper progression of cell division. Mutations or dysregulation of its expression are associated with the occurrence and development of various tumors, making Mps1 an important target in cancer research. Specific expression patterns and potential mutations of Mps1 in different cell types and tissues are under extensive investigation, aiming to develop targeted therapeutic strategies.