MKI67 and chordoma: In a patient with metastatic, poorly differentiated chordoma, clinical use of EZH2 inhibitor EPZ6438 resulted in a significant increase in intratumoral and stromal infiltration by proliferative (high Ki-67) CD8+ T cells, Foxp3+ regulatory T cells, and immune cells expressing checkpoint regulators PD-1 and LAG-3 (101), which meant both immuno-activating and suppressive effects.