TCEA1 is necessary for efficient RNA polymerase II transcription elongation past template-encoded arresting sites. TCEA1 has a role in suppression of transient pausing, which is the most important contribution of TCEA1 to elongation from a stall position. TCEA1 fuse to PLAG1 protein which is overexpressed in epithelial, myoepithelial, and mesenchymal-like tumor cells in tumors.