SNRPB2 (small nuclear ribonucleoprotein polypeptide B2) is a core spliceosomal component that functions as part of the U2 snRNP complex to facilitate pre-mRNA splicing and spliceosome assembly 1. Beyond its canonical splicing role, SNRPB2 exhibits critical oncogenic functions in cancer progression. In triple-negative breast cancer (TNBC), SNRPB2 promotes cell proliferation and invasion by controlling alternative splicing of MDM4 pre-mRNA, leading to downregulation of MDM4 and subsequent effects on the Rb1/E2F1 pathway 2. SNRPB2 also facilitates esophageal squamous cell carcinoma progression by stabilizing E2F4 protein and suppressing the Rb/E2F pathway 3. Additionally, intracellular CD28 recruits SNRPB2 to stabilize Cd274 (PD-L1) mRNA in cancer cell nuclei, promoting immune escape in TNBC 4. Clinically, SNRPB2 is upregulated across multiple cancer types and associated with poor prognosis 1. High SNRPB2 expression correlates with increased immune cell infiltration, suggesting dual roles in tumor progression and immune microenvironment modulation 3. SNRPB2 has emerged as a prognostic biomarker and potential therapeutic target for cancer immunotherapy, with knockdown studies demonstrating reduced cell proliferation in multiple myeloma 5 and enhanced chemotherapy sensitivity.