GSK 923295 is a potent and selective mitotic kinesin Centromere protein E (CENP-E) inhibitor, a protein that accumulates in the G2 phase of the cell cycle. It is proposed to be one of the motors responsible for mammalian chromosome movement and spindle elongation. GSK923295 induces mitotic arrest and chromosome alignment failure. It is reported to be a potent inhibitor of tumor cell growth, which is further enhanced when MEK/ERK signaling is also inhibited.