NELFCD (negative elongation factor complex member C/D) is a transcriptional regulatory protein functioning as a component of the NELF complex involved in RNA polymerase II pausing and negative regulation of transcription elongation 1. Beyond its canonical transcriptional role, NELFCD has emerged as a significant player in multiple disease contexts. In cancer biology, NELFCD promotes colon cancer progression by recruiting PRMT5 to the DUSP2 promoter, thereby repressing DUSP2 expression and activating the p38 MAPK signaling pathway 2. In colorectal cancer metastasis, eIF3i directly promotes NELFCD translation independent of transcriptional regulation, driving epithelial-mesenchymal transition and invadopodia formation 3. NELFCD knockdown inhibits CRC metastatic capacity, establishing it as a druggable target. Genetically, NELFCD variants are associated with disease progression: genetic studies identified NELFCD loci linked to jaundice-stage progression in primary biliary cholangitis, with eQTL analyses demonstrating that disease-associated SNPs influence NELFCD mRNA expression 4. Additionally, NELFCD emerged as an immune cell-specific genetic driver of migraine susceptibility 1, with drug repurposing identifying hydroxychloroquine sulfate as a potential therapeutic agent targeting NELFCD-associated migraine. Clinically, NELFCD represents a promising therapeutic target across multiple malignancies and immune-mediated diseases, with potential for precision medicine approaches.