Anti-Bcl-2 antibodies detect the protein encoded by the human gene, BCL2, also known as BCL2 apoptosis regulator. The full-length protein is 26,266 daltons in mass with 2 identified isoforms and is a member of the Bcl-2 family. The Bcl-2 antigen is a documented cancer marker. Anti-Bcl-2 antibodies detect the protein encoded by the human gene, BCL2, also known as BCL2 apoptosis regulator. The full-length protein is 26,266 daltons in mass with 2 identified isoforms and is a member of the Bcl-2 family. The Bcl-2 antigen is a documented cancer marker.