CDKL2 and gastric cancer: In this study, we found that CDKL2 protein expression was closely correlated with its copy number; both of them were tightly correlated with HER2 status and predicted a worse OS of GC patients, indicating that CDKL2 might have an oncogenic role in GC and was of important value in predicting HER2 status and prognosis of patients with GC.