**2.2 Nucleotide excision repair (NER) pathway**

NER is a DDR pathway responsible for repairing bulky DNA lesions induced by ultraviolet irradiation, carcinogens, and some chemotherapeutic agents such as cisplatin [57]. The involvement of NER pathway in DNA damage induced by chemotherapeutic drugs attracted researchers to investigate the association of NER activity with the response to these cytotoxic agents in various cancers. Although there are some controversies regarding the role of NER pathway in cancer, some studies showed direct correlations between NER activity and increased response to chemotherapy [15, 57]. Recent efforts in whole-genome sequencing and data analysis of The Cancer Genome Atlas have led to a better understanding of the roles of the molecules involved in this pathway and introduced NER genes as prognostic biomarkers of response to various DNA damaging chemotherapeutic in different types of cancers [15, 57–60].
