TCEA1 encodes transcription elongation factor A1 (also known as TFIIS or S-II), a nucleoplasmic protein essential for efficient RNA polymerase II transcription elongation. The primary function of TCEA1 is to facilitate transcription resumption at template-encoded arresting sites by cleaving nascent RNA transcripts, allowing polymerase to continue elongation from the new 3'-terminus 1. TCEA1 is a single-copy gene consisting of 10 exons spanning approximately 30 kb 1. TCEA1 has significant disease relevance across multiple pathways. TCEA1 deficiency impairs transcription elongation, leading to RNA polymerase II stalling at oxidative DNA damage sites, R-loop accumulation, telomere uncapping, and cellular senescence through paracrine signaling mechanisms 2. Additionally, TCEA1 is involved in cancer biology: it serves as a fusion partner with the PLAG1 oncogene in pleomorphic salivary gland adenomas through cryptic 8q rearrangements, promoting PLAG1 overexpression 3. TCEA1 has been identified as part of a prognostic biomarker panel for meningiomas and esophageal squamous cell carcinoma prognosis and immunotherapy response 45. TCEA1 recruitment at oncogene promoters can drive tumorigenesis through chr8 dynamics 6. An intronic lncRNA (lnc-TCEA1-3) regulates osteoclast function by modulating ATP6V1H expression, with implications for bone disease 7.