Anti-telomerase reverse transcriptase antibodies are used for the immunodetection of the protein encoded by the TERT gene. In humans, the canonical protein has a reported length of 1132 amino acid residues and a mass of 127 kDa. Its subcellular localization is in the nucleus and cytoplasm. Alternative splicing is reported to yield 4 different isoforms for this protein. It is noted to be expressed at a high level in thymocyte subpopulations, at an intermediate level in tonsil T-lymphocytes, and at a low to undetectable level in peripheral blood T-lymphocytes. A member of the Reverse transcriptase protein family, it is known to be involved with the cellular response to hypoxia and the regulation of apoptosis. Other names for this target antigen include DKCA2, DKCB4, EST2, PFBMFT1, TCS1, TP2, TRT, and CMM9. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Over 200 citations in the literature describe the use of telomerase reverse transcriptase antibodies in research. Western Blot is a widely used application for these antibodies. ELISA, Flow Cytometry, Immunofluorescence, and Immunohistochemistry are also common applications.