TTK and breast cancer: A tumor growth inhibition (TGI) study in the basal-a model of breast cancer HCC1806 implanted orthotopically in SCID mice resulted in a maximum TGI of 59% was observed upon oral administration of PF-7006 at 25 mg/kg every 3 days for 7 days (Q3Dx7) (Fig 4D) such that Mps1 was inhibited >90% periodically.