Our work provided results to show that the inhibition of COX-2 by NS-398 decreased the expression of DRP1 and mitochondrial fragmentation in the irradiated tumor cells, which was in line with the findings of Zhou [38], and that the down-regulation of mitochondrial COX-2 inhibited the stemness of nasopharyngeal carcinoma by decreasing the activity of DRP1. This evidence concerns the gene DNM1L and nasopharyngeal carcinoma.