GTF3C1 (general transcription factor IIIC subunit 1) is a core component of the TFIIIC complex required for RNA polymerase III-mediated transcription. It binds to box B promoter elements and initiates transcription complex assembly on tRNA genes and other pol III targets, including 5S rRNA and stable nuclear/cytoplasmic RNAs 1. Mechanistically, GTF3C1 functions within the TFIIIC2 complex where it interacts with regulatory proteins like SIRT7 to modulate pol III function and tRNA synthesis 1. The protein plays a critical role in ribosome biogenesis and protein synthesis regulation through its involvement in the mTOR signaling pathway. GTF3C1 has emerging relevance in multiple disease contexts. It was identified as a plausible candidate gene in esophageal atresia/tracheoesophageal fistula (EA/TEF) etiology, a rare congenital birth defect 2. Additionally, GTF3C1 expression associates with clinical outcomes: elevated expression correlates with poor prognosis in colorectal cancer patients and links to oncogenic pathways including WNT/β-catenin signaling 3. In triple-negative breast cancer, GTF3C1 was among 13 immune-related genes forming a prognostic signature predictive of distant recurrence-free survival 4. These findings suggest GTF3C1 may serve as both a developmental regulator and a potential prognostic biomarker in cancer biology.