VRK1 and squamous cell lung carcinoma: VRK1 specifically phosphorylates p53 in Thr18 resulting in its stabilization and transcriptional activation [14], [19]; and the resulting accumulation of p53 induces a proteolytic downregulation of VRK1 protein levels forming a novel autoregulatory loop [20] that is disrupted in lung squamous cell carcinomas with p53 mutations [21].