CDK5 and cancer: Cdk5 is expressed in various non-neuronal tissues [14–16] and has been implicated in various types of cancer including pancreatic [17–19], prostate [20, 21], thyroid [22, 23], glioma [24], pituitary [25], breast [26], lung [27], ovarian [28], and hepatocellular [29] cancers affecting various targets such as retinoblastoma protein and downstream cell cycle regulators [22, 23], the PIKE-A-Akt pathway [24], Ras-Ral signaling [17], or DNA damage response [29].