DNA repair system defects - role in oncogenesis and cancer therapy

Inherited and acquired abnormalities in DNA damage repair system may lead to cancer and other diseases, as well as to act as one of the key factors determining the patient’s responsiveness to chemo- and radiotherapy. Nowadays, the principles of the personalized therapy, based on specific features of disease development and pathogenesis of a solitary organism or in a small group, are applied to treat a broad number of diseases, including cancers. This approach allows to choose the most effective cancer therapy in every single case of cancer, based on the genetic analysis and expression level of specific proteins. One of the promising approaches for increasing the effectiveness of non-surgical cancer treatments - to develop the methods to increase the cancer cells sensitivity to conducted chemotherapy, based on using the DNA repair system defects for the better anti-cancer effect. The review covers some types of DNA repair system defects occurring while chemo- and radiotherapy. Perspectives of the possible influences on DNA repair mechanisms treated as possible targets for both anti-cancer treatment and for increasing the effects of cancer chemo- and radiotherapy, are discussed in the review considering the available published data and results of own research. DNA repair system defects play an important role in cancer genesis, but as well can determine the good response of patients with such defects to chemo- and radiotherapy (inducing different types of DNA damage).