ARN-3236 is a selective inhibitor of the kinase enzyme TTK (also known as MPS1), which plays a critical role in the spindle assembly checkpoint during cell division. By inhibiting TTK, ARN-3236 disrupts proper chromosome segregation, leading to mitotic catastrophe and apoptosis in rapidly dividing cells, particularly cancer cells. Its primary application is in cancer research, especially in the development of targeted therapies for tumors with chromosomal instability, such as certain breast, ovarian, and lung cancers. ARN-3236 has shown synergistic effects when combined with other antimitotic agents or DNA-damaging chemotherapeutics, enhancing tumor cell death in preclinical models. Due to its ability to override the spindle checkpoint, ARN-3236 is also used as a tool compound in studies investigating mitotic regulation, aneuploidy, and mechanisms of drug resistance in oncology. It holds potential as a lead candidate for therapies aimed at cancers that rely on robust checkpoint control to survive genomic instability.