RBM4 and head and neck squamous cell carcinoma: To this end, we sequentially transfected HNSCC cells with SEMA7A-WT/5NQ vectors and siRBM4 and observed that knockdown of RBM4 did not contribute to the AS of PD-L1 in SEMA7A-WT cells but significantly affected the SEMA7A-5NQ-mediated alteration in PD-L1 isoform transcription, indicating that deglycosylation of SEMA7A promoted PD-L1 AS isoform switching through upregulation of RBM4 (Fig. 9g, Supplementary Fig. 15c).