Moving From Poly (ADP-Ribose) Polymerase Inhibition to Targeting DNA Repair and DNA Damage Response in Cancer Therapy

J Clin Oncol. 2019 Sep 1;37(25):2257-2269. doi: 10.1200/JCO.18.02050. Epub 2019 May 3.


The DNA damage response (DDR) pathway coordinates the identification, signaling, and repair of DNA damage caused by endogenous or exogenous factors and regulates cell-cycle progression with DNA repair to minimize DNA damage being permanently passed through cell division. Severe DNA damage that cannot be repaired may trigger apoptosis; as such, the DDR pathway is of crucial importance as a cancer target. Poly (ADP-ribose) polymerase (PARP) is the best-known element of the DDR, and several PARP inhibitors have been licensed. However, there are approximately 450 proteins involved in DDR, and a number of these other targets are being investigated in the laboratory and clinic. We review the most recent evidence for the clinical effect of PARP inhibition in breast and ovarian cancer and explore expansion into the first-line setting and into other tumor types. We critique the evidence for patient selection techniques and summarize what is known about mechanisms of PARP inhibitor resistance. We then discuss what is known about the preclinical rationale for targeting other members of the DDR pathway and the associated tumor cell genetics that may confer sensitivity to these agents. Examples include DNA damage sensors (MLH1), damage signaling molecules (ataxia-telangiectasia mutated; ataxia-telangiectasia mutated-related and Rad3-related; CHK1/2; DNA-dependent protein kinase, catalytic subunit; WEE1; CDC7), or effector proteins for repair (POLQ [also referred to as POLθ], RAD51, poly [ADP-ribose] glycohydrolase). Early-phase clinical trials targeting some of these molecules, either as a single agent or in combination, are discussed. Finally, we outline the challenges that must be addressed to maximize the therapeutic opportunity that targeting DDR provides.

Publication types

  • Review

MeSH terms

  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / enzymology
  • Breast Neoplasms / genetics*
  • Clinical Trials, Phase III as Topic
  • DNA Damage*
  • DNA Repair / drug effects*
  • Drug Resistance, Neoplasm
  • Female
  • Humans
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / enzymology
  • Ovarian Neoplasms / genetics*
  • Poly(ADP-ribose) Polymerase Inhibitors / pharmacology
  • Poly(ADP-ribose) Polymerase Inhibitors / therapeutic use*
  • Randomized Controlled Trials as Topic


  • Poly(ADP-ribose) Polymerase Inhibitors