The poly ADP-ribosylation is one of post translational modification of proteins, and is the addition of many ADP-ribose moieties to a protein. This protein modification is carried out by the poly ADP-ribose polymerases (PARPs), which are found in most eukaryotes, but not prokaryotes or yeast. The reaction is involved in various cellular processes and conditions, including DNA repair, transcriptional control, genomic stability, cell death and transformation, and several reports have been indicated in relation to cancer and autoimmune disease (ref. 1-4). This antibody reacts specifically to poly ADP-ribose (PAR) (ref. 4, 5).