However, it has also been reported that an increase in the gene expression level of DDR genes may lead to resistance to cisplatin chemotherapy [68], while the overexpression of BRCA1, BRCA2, RAD51 and RPA1 has been observed in hypopharyngeal and nasopharyngeal carcinoma cells resistant to radiotherapy [69]. This evidence concerns the gene RAD51 and nasopharyngeal carcinoma.