DNA repair inhibitors in cancer treatment.

Chemotherapy and radiation are two important modalities for cancer treatment. Many agents in clinical used have the ability to induce DNA damage, however they may be highly cytotoxic as a secondary effect. Different mechanisms are involved both, in detection and repair of DNA damage. The modulation of these pathways, has a great impact on clinical outcome and is frequently responsible of therapeutic resistance. Therefore, pharmacological inhibition of DNA damage repair pathways has been explored as a useful strategy to enhance chemo and radiosensitivity, thus it could be used for reversing drug resistance. Different agents have shown excellent results in preclinical studies in combination with radiation or chemotherapy. Early phase clinical trials are now being carried out using different DNA repair inhibitors targeting several enzymes such as PARP, DNA-PK or MGMT.