PGP and neoplasm: The CCK-8 assay results showed that IC50 of anti-tumor drug doxorubicin on KG-1 cells was decreased (Fig. 3c), and drug-resistant proteins MRP1 and P-GP showed down-regulated expression (Fig. 3d–f) after silencing XIST, which was rescued by overexpression of MYC (all p < 0.05).