Anti-PBX homeobox 3 antibodies are used in the immunodetection of the protein encoded by the PBX3 gene. In humans, the canonical protein has a reported length of 434 amino acid residues and a mass of 47.2 kDa. Its subcellular localization is in the nucleus. Alternative splicing is reported to yield 5 different isoforms for this protein. It is ubiquitously expressed across many tissue types. A member of the TALE/PBX homeobox protein family, it is reported to be a transcriptional activator that binds the sequence 5'-ATCAATCAA-3'. Other names for this target antigen include homeobox protein PBX3, pre-B-cell leukemia homeobox 3, and pre-B-cell leukemia transcription factor 3.