The results showed that peripheral eosinophil and tumor-infiltrated eosinophil counts decreased with increased KI67 proliferation index, peripheral eosinophil counts deceased after tumor recurrence, and eosinophils could inhibit chordoma cells proliferation by inducing apoptosis and secreting inflammatory cytokines (TNF-α, IL-2 and IFN-γ); moreover, this apoptotic effect could be reversed by blocking TNF-α. This evidence concerns the gene MKI67 and chordoma.