SNAPC5 is a subunit of the snRNA Activating Protein Complex (SNAPc), a multifunctional basal transcription factor required for transcription of both RNA polymerase II and III small nuclear RNA genes 1. SNAPC5 functions as part of the SNAPc complex to bind the proximal sequence element (PSE), a non-TATA-box core promoter element, and recruit transcription factors including TBP and BRF2 to establish pre-initiation complexes 2. Structurally, SNAPC5 is positioned near promoter DNA within the Pol III pre-initiation complex assembled on U6 snRNA promoters, as revealed by cryo-EM and crosslinking mass spectrometry, with distinct mechanisms enabling SNAPc engagement across both polymerase types 3. Beyond its canonical transcription function, SNAPC5 has emerged as a disease-relevant gene in cancer biology. It was identified as one of five cancer-dependent genes in a prognostic signature for colon cancer, where high expression correlated with worse survival outcomes and reduced chemotherapy response 4. Additionally, a long non-coding RNA derived from the SNAPC5 locus (lnc-SNAPC5-3:4) was discovered in plasma exosomes as a potential biomarker for monitoring anlotinib treatment efficacy in advanced non-small cell lung cancer, with upregulation indicating treatment response 5. SNAPC5 was also identified among co-expressed genes associated with glioma pathogenesis in transcriptomic analyses 6, suggesting broader clinical relevance in malignant brain tumors.