VRK1 and breast carcinoma: Moreover, several studies have suggested the involvement of VRK1 overexpression and its correlation with poor prognosis in many cancer types such as head and neck squamous cell carcinoma (HNSCC) [24], lung cancer [25], hepatocellular carcinoma (HCC) [26,27], esophageal cancer [28], glioma [29] or breast cancer [30].