MKI67 and neoplasm: Treatment with GCN2iB at 30 mg/kg twice daily for 2–6 weeks resulted in robust anti-tumor activity in all four models as shown by a significant delay in the tumor volume, reductions in tumor mass at endpoint, and reduced expression of p-GCN2-T899 and Ki-67 (Figure 7A–E and Figure 7—figure supplement 1A).