KHDC4 (KH domain containing 4) is an RNA-binding protein functioning as a pre-mRNA splicing factor. It contains KH domains that mediate preferential binding to A/C-rich sequences and poly-C stretches in RNA 1. KHDC4 interacts with the PRP19C/Prp19 complex (NTC/Nineteen complex), a core spliceosomal component involved in the second catalytic step of splicing and spliceosome assembly 2. The protein regulates splice site selection, with overexpression altering both 5' and 3' splice site utilization 2. Clinically, KHDC4 exhibits significant disease relevance in cancer. In prostate cancer, KHDC4 expression is elevated in late-stage and lymph node metastatic tumors, positively correlating with poor overall and disease-free survival 3. The KHDC4-TRAF2 axis contributes to tumor malignancy features, with KHDC4/TRAF2 distribution showing superior prognostic correlation with Gleason score compared to PSA 3. In breast cancer, KHDC4 functions as a potential miR-641 target within a ceRNA regulatory network, with miR-641 overexpression inhibiting cell proliferation and invasion 4. These findings suggest KHDC4 may serve as a prognostic biomarker for advanced cancer and a potential therapeutic target.