Anti-CPX chromosome region candidate 1 antibodies are used for the immunodetection of the protein encoded by the CPXCR1 gene. In humans, the canonical protein has a reported length of 301 amino acid residues and a mass of 34.7 kDa. It is reported to be expressed in a variety of fetal tissues. Other names for this target antigen include CPX chromosomal region candidate gene 1 protein, cancer/testis antigen 77, and CT77. Gene orthologs have been identified in the mouse and chimpanzee species.