ABCB1 and central nervous system cancer: Functional assays confirmed that POLR2J4 promotes glioma progression and cisplatin resistance, while mechanistic studies showed that POLR2J4 knockdown downregulates key drug resistance genes (ABCB1, ABCC1, BCL2), reduces serum levels of IL-6 and TGF-β1, and suppresses TGF-β1 and PD-L1 expression in tumor tissues, underscoring its role in shaping an immunosuppressive, drug-resistant microenvironment.