Although negative DNA-PKcs (DNA-dependent protein kinase catalytic subunit, also known as PRKDC) expression has been reported to be found in about 20% (114/564) of human gastric cancers and be associated with gastric cancer progression and poor patient survival, especially for stage I gastric cancer patients [23,24], it is positively expressed in 36.8% (82/223) of nasopharyngeal carcinoma tissues and is in association with low 5-year overall survival rate [25]. This evidence concerns the gene PRKDC and gastric cancer.