PARP1, short for poly (ADP-ribose) polymerase 1, is an enzyme that plays a pivotal role in DNA repair, maintenance of genomic integrity, and regulation of various metabolic and signaling processes. Discovered over 50 years ago, PARP1 has gradually been recognized for its critical functions in cellular biology. PARP1 catalyzes the transfer of ADP-ribose residues from NAD+ to target substrates, resulting in the formation of a poly (ADP-ribose) (PAR) chain. This PAR modification, known as PARylation, facilitates PARP1's involvement in DNA repair, stabilization of DNA replication forks, and modulation of chromatin structure. The primary functions of PARP1 can be described in four aspects: DNA base excision repair (BER), suppression of transcription from damaged DNA, depletion of cellular energy leading to apoptosis, and participation in transcriptional regulation of certain genes. The loss of PARP1 function has been associated with increased risk of cancers such as breast and lung cancer.