CDK5R1 and cancer: Among the strongest expressed ones, it is of interest to note that BTG4 and RERG are known to bare anti-proliferative function in several cancers [30, 31, 44–48], that the peptidase inhibitor P16 inhibits cell proliferation in non cancerous cells [49, 50] and acts as a paralog of GLIPR1 (Glioma Pathogenesis related protein 1), a CAP/CRIPS protein associated with cell growth suppression and proapoptotic activities in multiple cancer cell lines including glioma [51], and finally that SERTAD1 and CDK5R1 were shown to have a specific role in neuronal cell death [52, 53].