Supplemental Figure 1C shows the predicted pathway of IFN-γ-induced PD-L1 expression, as deduced from the results of microarray analysis. The transcription factor CEBPD is induced by IFN-γ, leading to inhibition of MYC and activation of TLR9, IL10, and TNF, and culminating in upregulation of PD-L1 (CD274) expression. Taken together, these results suggest that CEBPD is potentially involved in the pathway of IFN-γ-induced PD-L1 expression in chordoma cells. The gene discussed is TLR9; the disease is chordoma.